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SAKAGAMI Kimihiro
Graduate School of Engineering / Department of Architecture
Professor

Researcher basic information

■ Research Keyword
  • Urban acoustic environment
  • Acoustics Education
  • Acoustical Materials
  • Environmental Acoustics
  • Architectural Environmental Engineering
■ Research Areas
  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Construction environment and equipment
■ Committee History
  • 2021 - Present, Acoustics Australia, Editorial Board
  • Jan. 2020 - Present, MDPI, Editorial Board, Urban Science
  • 2019 - Present, MDPI, Editorial Board, Applied Sciences
  • 2011 - Dec. 2021, Elsevier, Applied Acoustics Associate Editor / Editor
  • 2018 - 2021, MDPI, Guest Editor, Sustainability
  • Sep. 2020 - Dec. 2020, Frontier Science Psychology ゲストエディター
  • 2009 - 2011, 日本音響学会, 理事
  • 2009 - 2011, 日本音響学会建築音響研究委員会, 委員長
  • 2007 - 2009, 日本音響学会, 建築音響研究委員会副委員長
  • 日本音響学会, 評議員

Research activity information

■ Award
  • Mar. 2012 日本音響学会, 日本音響学会環境音響研究賞, 次世代吸音材料を用いた吸音構造に関する研究
    SAKAGAMI KIMIHIRO
    Japan society

■ Paper
  • Kimihiro Sakagami, Kaito Katayama
    Acoustical Society of Japan, Dec. 2024, Acoustical Science and Technology, 46(1) (1), 30 - 33, English
    [Refereed]
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    Acoustical Society of Japan, Mar. 2024, Acoustical Science and Technology, 45(2) (2), 57 - 68
    Scientific journal

  • Kimihiro Sakagami, Haruhi Inoue, Takeshi Okuzono
    Demands for natural ventilation is inaugurated recently, particularly after the COVID-19 outbreak. Various ventilating windows have been proposed, one of which a plenum window has been studied for these years. Since the COVID outbreak shops and restaurants often leave doors opened for ventilation reasons during their business hours. However, by this, the indoor sound environment is suffered by incoming noises from streets. Therefore, it is desirable that a sound insulation structure enabling natural ventilation is developed. In this study, we propose a door with plenum structure which is an application of the same principle of plenum windows to a door. Doors and windows are of different sizes, and under different conditions. Therefore, in this paper, as a pilot study, we employed finite element method to analyse the sound insulation characteristics of a plenum door. Results show that a plenum door, although its sound insulation is not very high, shows sound insulation performance to a certain extent. Also, a parametric study is given to show the effect of parameters including that of sound absorption linings.
    Institute of Noise Control Engineering (INCE), Nov. 2023, INTER-NOISE and NOISE-CON Congress and Conference Proceedings, 268(2) (2), 6318 - 6327
    Scientific journal

  • Yohei Tsukamoto, Kaoru Tamai, Kimihiro Sakagami, Takeshi Okuzono
    Since double-glazed glasses have superior thermal insulation performance compared to single-glazed glasses, they are widely employed for windows in recent buildings. However, the double-glazed glasses used in general buildings have mass-air-mass resonance at around 200-400 Hz, and, at those frequencies, their sound reduction indices are often lower than that of single-glazed glasses that have the same weight. In designing an indoor acoustic environment, it is helpful to have a practical method to predict the sound reduction index of a double-glazed glass window, including the resonance. In this study, at first, measured values of actual double-glazed windows are compared with calculated values of the existing sound transmission theories for double plates and applicability of the theories to double-glazed windows are investigated. Next, in order to obtain a practical prediction of the sound reduction indices of double-glazed windows, some measured values of double-glazed windows are collected from a manufacturer's database and the characteristics of the sound reduction indices are discussed.
    Institute of Noise Control Engineering (INCE), Nov. 2023, INTER-NOISE and NOISE-CON Congress and Conference Proceedings, 268(7) (7), 1297 - 1307
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    Time-domain room acoustic modeling using mass-lumped higher-order tetrahedral finite elements with an explicit time-marching scheme is highly attractive because of its excellent geometrical flexibility with unstructured meshing and applicability into massively parallel computing. However, the standard mass-lumped tetrahedral elements yield an unstable scheme, and only implicit time-marching schemes are available. This study proposes a novel wave-based room acoustics solver based on a high-order explicit time-domain FEM. The present solver uses mass-lumped 15-node tetrahedral elements for spatial discretization and a dissipation-free two-stage partitioned Runge-Kutta time integration for time discretization. The 15-node tetrahedral elements had been developed to apply mass-lumping methods to 10-node tetrahedral elements, which are the most common finite element in engineering applications, but its applicability in room acoustics problems is unknown. Higher accuracy and efficiency of the proposed method over the standard method using 10-node tetrahedral elements is presented through an eigenvalue analysis of a long duct model and acoustic simulations in a small room. Additionally, frequency-dependent sound absorbing boundary is implemented by revising an auxiliary differential equation method.
    Institute of Noise Control Engineering (INCE), Nov. 2023, INTER-NOISE and NOISE-CON Congress and Conference Proceedings, 268(3) (3), 5251 - 5261
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    This paper presents a proposal of an efficient binaural room-acoustics auralization method, an essential goal of room-acoustics modeling. The method uses a massively parallel wave-based room-acoustics solver based on a dispersion-optimized explicit time-domain finite element method (TD-FEM). The binaural room-acoustics auralization uses a hybrid technique of first-order Ambisonics (FOA) and head-related transfer functions. Ambisonics encoding uses room impulse responses computed by a parallel wave-based room-acoustics solver that can model sound absorbers with complex-valued surface impedance. Details are given of the novel procedure for computing expansion coefficients of spherical harmonics composing the FOA signal. This report is the first presenting a parallel wave-based solver able to simulate room impulse responses with practical computational times using an HPC cloud environment. A meeting room problem and a classroom problem are used, respectively, having 35 million degrees of freedom (DOF) and 100 million DOF, to test the parallel performance of up to 6144 CPU cores. Then, the potential of the proposed binaural room-acoustics auralization method is demonstrated via an auditorium acoustics simulation of up to 5 kHz having 750,000,000 DOFs. Room-acoustics auralization is performed with two acoustics treatment scenarios and room-acoustics evaluations that use an FOA signal, binaural room impulse response, and four room acoustical parameters. The auditorium acoustics simulation showed that the proposed method enables binaural room-acoustics auralization within 13,000 s using 6144 cores.
    MDPI AG, Feb. 2023, Applied Sciences, 13(5) (5), 2832 - 2832
    Scientific journal

  • Yohei Tsukamoto, Kaoru Tamai, Kimihiro Sakagami, Takeshi Okuzono, Yoshihiro Tomikawa
    Acoustical Society of Japan, Nov. 2022, Acoustical Science and Technology, 43(6) (6), 335 - 338
    Scientific journal

  • Designable heterogeneous MPPs and their applications
    Kimihiro Sakagami, Midori Kusaka, Takeshi Okuzono
    Lead, Oct. 2022, Proc. of 24th International Congress on Acoustics, Gyeong-ju, Korea, ABS-0482, English
    [Invited]
    International conference proceedings

  • Marie Mimura, Yohei Tsukamoto, Yoshihiro Tomikawa, Takeshi Okuzono, Kimihiro Sakagami
    Acoustical Society of Japan, Sep. 2022, Acoustical Science and Technology, 43(5) (5), 276 - 279
    Scientific journal

  • Marie Mimura, Takeshi Okuzono, Kimihiro Sakagami
    This paper presents discussion of the prediction capability of three numerical models using finite element method for predicting the sound reduction index (SRI) of fixed windows having different dimensions in a laboratory environment. The three numerical models tested here only discretize the window part or windows part and the space around the windows to reduce the necessary computational cost for vibroacoustics simulations. An ideal diffused sound incidence condition is assumed for three models. Their predictability and numerical efficiency were examined over five fixed windows with different dimensions compared to measured SRIs. First, the accuracy of the simplest model in which the window part is only discretized with finite elements was examined. Acoustic radiation to the transmission field is computed using Rayleigh’s integral. Calculations were performed under two loss factor setups respectively using internal loss factors of each material and measured total loss factor of each window. The results were then compared with the measured values. Results revealed the effectiveness of using the measured total loss factor at frequencies around and above the coincidence frequencies. Subsequently, we tested the prediction accuracy of a numerical model that includes a niche existing in a laboratory environment. Also, hemispherical free fields around the window are discretized using fluid elements and infinite fluid elements. The results underscored the importance of including a niche in a numerical model used to predict sound reduction index below 1 kHz for smaller windows accurately. Nevertheless, this numerical model, including a niche, entails high computational costs. To enhance the prediction efficiency, we examined the applicability of a weak-coupling model that divides calculation procedures into three steps: (1) incidence field calculation to the window surface, (2) sound transmission calculation in fixed windows, and (3) sound radiation calculation from a window surface to a transmission field. Results revealed that the weak-coupling model produces almost identical results to those of a strong-coupling model, but with higher efficiency.
    Frontiers Media SA, Aug. 2022, Frontiers in Built Environment, 8
    Scientific journal

  • Kimihiro Sakagami, Midori Kusaka, Takeshi Okuzono
    Recently, dotted-art MPPs have been proposed in which a designed pattern is made with the holes. In such a case, the MPP becomes heterogeneous in general. However, existing theories used for the prediction of the absorption characteristics of MPPs assume homogeneity. Therefore, the elaboration of a method for heterogeneous MPPs needs to be performed. In previous work, the authors proposed a method to predict the absorption characteristics of a heterogeneous MPP by using synthesized impedances of each part with different parameters; this is called the synthetic impedance method (SIM) in the present paper. The SIM can potentially be used for various heterogeneous MPPs; however, its scope of applicability needs to be clarified. Furthermore, in proposing a design concept of dotted-art heterogeneous MPPs, the condition that would make the designed MPPs fall within the scope of the SIM needs to be determined. Therefore, in this study, in order to clarify the scope of the applicability of the SIM, twelve samples are first prepared, and then measured sound absorption characteristics and predicted ones are compared and examined in terms of prediction errors. The results show that there are two conditions that should be met to produce predictable heterogeneous MPPs: (1) holes are distributed over the entire surface of the specimen, and (2) the hole spacing is constant. Considering these conditions, a design concept for a dotted-art heterogeneous MPP is proposed: two types of holes, larger holes for the pattern and smaller holes for the background, should be used to meet the above two conditions. Case studies with nine prototypes show that the SIM can make predictions for dotted-art heterogeneous MPPs fabricated according to the concept described above.
    MDPI AG, Jul. 2022, Acoustics, 4(3) (3), 588 - 608, English
    Scientific journal

  • Iwan Prasetiyo, Khoerul Anwar, Ferio Brahmana, Kimihiro Sakagami
    Last, Elsevier BV, Jun. 2022, Applied Acoustics, 195, 108842 - 108842, English
    [Refereed]
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    Wave-based acoustics simulation methods such as finite element method (FEM) are reliable computer simulation tools for predicting acoustics in architectural spaces. Nevertheless, their application to practical room acoustics design is difficult because of their high computational costs. Therefore, we propose herein a parallel wave-based acoustics simulation method using dissipation-free and dispersion-optimized explicit time-domain FEM (TD-FEM) for simulating room acoustics at large-scale scenes. It can model sound absorbers with locally reacting frequency-dependent impedance boundary conditions (BCs). The method can use domain decomposition method (DDM)-based parallel computing to compute acoustics in large rooms at kilohertz frequencies. After validation studies of the proposed method via impedance tube and small cubic room problems including frequency-dependent impedance BCs of two porous type sound absorbers and a Helmholtz type sound absorber, the efficiency of the method against two implicit TD-FEMs was assessed. Faster computations and equivalent accuracy were achieved. Finally, acoustics simulation of an auditorium of 2271 m3 presenting a problem size of about 150,000,000 degrees of freedom demonstrated the practicality of the DDM-based parallel solver. Using 512 CPU cores on a parallel computer system, the proposed parallel solver can compute impulse responses with 3 s time length, including frequency components up to 3 kHz within 9000 s.
    Last, MDPI AG, Jan. 2022, Buildings, 12(2) (2), 105 - 105, English
    [Refereed][Invited]
    Scientific journal

  • Shunichi Mukae, Takeshi Okuzono, Kimihiro Sakagami
    Partition of unity finite element method with plane wave enrichment (PW-FEM) uses a shape function with a set of plane waves propagating in various directions. For room acoustic simulations in a frequency domain, PW-FEM can be an efficient wave-based prediction method, but its practical applications and especially its robustness must be studied further. This study elucidates PW-FEM robustness via 2D real-scale office room problems including rib-type acoustic diffusers. We also demonstrate PW-FEM performance using a sparse direct solver and a high-order Gauss–Legendre rule with a recently developed rule for ascertaining the number of integration points against the classical linear and quadratic FEMs. Numerical experiments investigating mesh size and room geometrical complexity effects on the robustness of PW-FEM demonstrated that PW-FEM becomes more robust at wide bands when using a mesh in which the maximum element size maintains a comparable value to the wavelength of the upper-limit frequency. Moreover, PW-FEM becomes unstable with lower spatial resolution mesh, especially for rooms with complex shape. Comparisons of accuracies and computational costs of linear and quadratic FEM revealed that PW-FEM requires twice the computational time of the quadratic FEM with a mesh having spatial resolution of six elements per wavelength, but it is highly accurate at wide bands with lower memory and with markedly fewer degrees of freedom. As an additional benefit of PW-FEM, the impulse response waveform of quadratic FEM in a time domain was found to deteriorate over time, but the PW-FEM waveform can maintain accurate waveforms over a long time.
    Last, MDPI AG, Jan. 2022, Acoustics, 4(1) (1), 53 - 73, English
    [Refereed][Invited]
    Scientific journal

  • Marie Mimura, Takeshi Okuzono, Kimihiro Sakagami
    Last, Acoustical Society of Japan, Jan. 2022, Acoustical Science and Technology, 43(1) (1), 32 - 42, English
    [Refereed]
    Scientific journal

  • Shunichi Mukae, Takeshi Okuzono, Kanako Tamaru, Kimihiro Sakagami
    Last, Elsevier BV, Jan. 2022, Applied Acoustics, 185, 108383 - 108383, English
    [Refereed]
    Scientific journal

  • Yohei Tsukamoto, Kaoru Tamai, Kimihiro Sakagami, Takeshi Okuzono, Yoshihiro Tomikawa
    Acoustical Society of Japan, Nov. 2021, Acoustical Science and Technology, 42(6) (6), 350 - 353, English
    [Refereed]
    Scientific journal

  • Takeshi Okuzono, Takumi Yoshida, Kimihiro Sakagami
    Last, Elsevier BV, Nov. 2021, Applied Acoustics, 182, 108212 - 108212, English
    [Refereed]
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    Last, Acoustical Society of Japan, Sep. 2021, Acoustical Science and Technology, 42(5) (5), 270 - 281, English
    [Refereed]
    Scientific journal

  • Kanako Tamaru, Takeshi Okuzono, Shunichi Mukae, Kimihiro Sakagami
    Last, Acoustical Society of Japan, Sep. 2021, Acoustical Science and Technology, 42(5) (5), 231 - 240, English
    [Refereed]
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Yui Sugimoto, Kimihiro Sakagami
    Accurate boundary modelings that address the frequency-dependent sound absorption characteristics of various sound absorbers are crucial for wave-based room acoustic simulation. In time-domain simulations, however, a computationally demanding convolution appears in frequency-dependent impedance boundary conditions. The present paper proposes a room acoustic solver with a fourth-order accurate explicit TD-FEM, incorporating a frequency-dependent absorbing boundary condition efficiently using a recursive convolution method, namely the auxiliary differential equation (ADE) method. Its performance against the fourth-order accurate frequency-domain FEM is examined via 2D real-scale room acoustic problems, solving a sound propagation in an office room up to 4.5 kHz. Firstly, we describe briefly the formulation of the proposed room acoustics solver based on the explicit TD-FEM. Then, the discretization error property of the proposed method is evaluated via an impedance tube problem, including a frequency-dependent impedance boundary of porous sound absorber. Finally, the accuracy and efficiency of the proposed method are demonstrated with the comparison of frequency-domain FEM solver, which uses a sparse direct solver for the solution of the linear system at each frequency. Results showed the proposed method can perform an acoustic simulation with significantly low computational costs compared to the frequency-domain solver while keeping an acceptable level of accuracy.
    Institute of Noise Control Engineering (INCE), Aug. 2021, INTER-NOISE and NOISE-CON Congress and Conference Proceedings, 263(5) (5), 1120 - 1129
    Scientific journal

  • Kimihiro Sakagami, Midori Kusaka, Takeshi Okuzono, Shigeyuki Kido, Daichi Yamaguchi
    There are various measures currently in place to prevent the spread of coronavirus (COVID-19); however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets, as including a hole-free panel is important to prevent possible droplet penetration. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings on the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. For this study, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.
    UCL Press, Jul. 2021, UCL Open Environment, 2(9) (9)
    [Refereed]
    Scientific journal

  • Midori Kusaka, Kimihiro Sakagami, Takeshi Okuzono
    Micro-perforated panels (MPPs) are one of the most promising alternatives to conventional porous sound-absorbing materials. Traditionally, the theory of the sound absorption properties of MPPs is based on the assumption that MPPs are a homogeneous material with identical pores at regular intervals. However, in recent years, some MPPs have not met these conditions, and although a variety of designs have been created, their properties and prediction methods were studied in only fewer works. In this paper, considering the wide variety of MPP designs, we made a trial production of heterogeneous MPPs, which are MPPs with holes of different diameters, and studied the prediction method applicable to these MPPs. We measured the normal incidence sound absorption characteristics of those MPPs, backed by a rigid backing and air-cavity in-between, in an impedance tube. The prediction method proposed in this work is to treat the heterogeneous MPPs as combinations of several homogeneous components, and to combine them after applying the existing theory on homogeneous MPPs to each component. As a result, except in a few cases, the measured and predicted values of the absorption properties agreed relatively well. We also found that the arrangement of the holes in the material and the depth of the back cavity affected the agreement between the measured and predicted results.
    Corresponding, MDPI AG, Jul. 2021, Acoustics, 3(3) (3), 473 - 484, English
    [Refereed]
    Scientific journal

  • Yohei Tsukamoto, Kimihiro Sakagami, Takeshi Okuzono, Yoshihiro Tomikawa
    As a basic study of a practical method for predicting the sound insulation performance of windows, this report presents a study of the sound reduction index of windows with single glazing, below a critical frequency. First, the results calculated by an existing theory for a single plate for the sound reduction indices are compared with measured results of actual windows to assess the theory’s applicability for evaluating the sound insulation performance of windows. Then, a regression analysis is employed to measure the results of a certain number of actual windows to explore a further development of a more practical prediction. The following findings were obtained: (1) Sound reduction indices of actual fixed windows are predictable using Sewell’s transmission theory for a single plate. However, sound reduction indices of openable windows, especially those of sliding windows, are strongly affected by gaps in the window frame. Therefore, predicting sound reduction indices of all windows accurately is difficult if using only one theory. (2) The frequency slope of the window reduction index is much lower than that of the mass law. Regression analyses indicate that the frequency slope of the reduction index of all examined windows is 3.0 dB per octave, on average.
    UCL Press, May 2021, UCL Open Environment, (2)(06) (06), English
    [Refereed]
    Scientific journal

  • Performance of a dispersion-optimized explicit fem in room acoustic simulations including impedance boundaries
    Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    The development of a computationally efficient wave-based room acoustic solver is an active research area in the architectural acoustics field, thanks to both the progress in computational technology and attractiveness for accurate acoustic modeling in virtual spaces. The authors have been proposed an efficient acoustic solver with fourth-order accurate explicit FEM using a dispersion-reduced low-order element and a modified time integration and shown its applicability to real-scale room acoustic modeling up to several kilohertz. However, the method has the drawback of having a dissipation property. The present paper proposes dissipation-free explicit FEMs for acoustic simulations to overcome the drawback. We also present the dispersion-optimized method that can produce an accurate result at a high frequency. As a numerical demonstration of the two proposed methods' effectiveness, we show that the developed two acoustic solvers have higher accuracy and efficiency than the standard implicit FEM via acoustic simulations in a cubic room with impedance boundaries.
    Silesian University Press, 2021, "Advances in Acoustics, Noise and Vibration - 2021" Proceedings of the 27th International Congress on Sound and Vibration, ICSV 2021, English
    International conference proceedings

  • Kimihiro Sakagami, Takeshi Okuzono
    In this study, we first point out the possible acoustic problems associated with the post-pandemic operation of built environments. In particular, we focus on the problem of acoustic deficiency due to the lack of absorption. This deficiency, which is likely to be encountered in most enclosed spaces in a range of establishments, is due to the reduced number of audience members or users of the space as a result of social distancing. As one of the promising solutions to this problem, we introduce a sound absorption technique using three-dimensional (3D) space sound absorbers developed through our recent research projects. Significantly, the type of sound absorber proposed herein is made of materials that are especially suited to hygiene considerations. The materials are microperforated panels (MPPs) and permeable membranes (PMs), both of which are easily washable and sanitised. Furthermore, we point out that 3D-MPP or PM space absorbers possess the additional value of aesthetic designability.
    UCL Press, Nov. 2020, UCL Open Environment, (1) (1), 1 - 10, English
    [Refereed][Invited]
    Scientific journal

  • Kimihiro Sakagami
    This communication compares the previously reported results of the acoustic environment, mainly noise levels at a fixed point, in a quiet residential area in Kobe, Japan, under the declaration of the COVID-19 state of emergency in May 2020 with the results of two follow-up studies in the same area: subsequent follow-up noise measurements in June and July–August 2020, and the present results of measurements in September–October 2020. The results of the comparison among the above three measurements suggest that noise levels were lower during September-October 2020 than during the declaration of the state of emergency in May 2020. In the period from May to October 2020, the noise level was significantly higher in July and August of the same year due to the sound of cicadas, which are common in this area. This suggests that it is difficult to set the target values of the acoustic environment planning by referring to the low noise level at lockdown or similar measures in areas with large seasonal variations in acoustic environment. Although many case studies are necessary to obtain appropriate target values, one case study is presented in this communication to illustrate an example and discuss its difficulty.
    MDPI AG, Nov. 2020, Urban Science, 4(4) (4), 63 - 63, English
    [Refereed][Invited]
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    Last, Acoustical Society of Japan, Nov. 2020, Acoustical Science and Technology, 41(6) (6), 837 - 840, English
    [Refereed]
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    Last, Acoustical Society of Japan, Nov. 2020, Acoustical Science and Technology, 41(6) (6), 819 - 822, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Midori Kusaka, Takeshi Okuzono, Shigeyuki Kido, Daichi Yamaguchi
    Acoustical Society of Japan, Sep. 2020, Acoustical Science and Technology, 41(5) (5), 784 - 787, English
    [Refereed]
    Scientific journal

  • A note on the acoustic environment in a usually quiet residential area after the 'state of emergency' declaration due to COVID-19 pandemic in Japan was lifted: supplementary survey results in post-emergency situations
    SAKAGAMI, Kimihiro
    Sep. 2020, Noise Mapping, 7, 1 - 7, English
    [Refereed]
    Scientific journal

  • Three-dimensional MPP space absorbers: An overview of the project and recent development
    Midori Kusaka, Kimihiro Sakagami, Takeshi Okuzono, Shigeyuki Kido, Daichi Yamaguchi
    A micro-perforated panel (MPP) is one of the most promising alternatives of absorbers for its durability, designability, and eco-friendliness. It is typically used with a rigid wall and air-layer between them, forming a Helmholtz resonator. However, this type can be used in limited situations. In order to use it more widely, various MPP space absorbers without any backing structures have been proposed. We proposed three-dimensional MPP absorbers (3-D MPA), i.e., a cylindrical and a rectangular MPP space absorber (CMSA and RMSA), which are superior to other absorbers in terms of wide possibility of arrangement: they can be suspended from the ceiling, or put on the floor. To make 3-D MPA useful for much wider range of applications, a trial production of a spherical MPP space absorber (SMSA) is made. In this paper, as a background the main results of CMSA and RMSA are overviewed. Then, the absorption characteristics of SMSA are measured in a reverberation chamber, and compared with those of CMSA and RMSA. As a result, SMSA shows a resonance peak at around 400 Hz: it is higher than CMSA and RMSA. The results show an SMSA can be used as a space sound absorber in practical situations.
    Korean Society of Noise and Vibration Engineering, Aug. 2020, Proceedings of 2020 International Congress on Noise Control Engineering, INTER-NOISE 2020, English
    International conference proceedings

  • A formulation of time-domain FEM for room acoustic simulations with frequency-dependent locally-reacting impedance boundary
    Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    A room acoustic simulator using time-domain finite element method (TD-FEM) has been broadened its applicable range as a room acoustic design tool, recently. In the acoustic TD-FEM, constructing various sound absorber model is of crucial importance to perform reliable simulations. However, an accurate time-domain extended-reacting sound absorber model, which can take account for both frequency and incident angle dependence of sound absorption characteristics, has not been developed sufficiently due to the difficulties of modeling. The major difficulty is how to reflect frequency-dependent absorption characteristics efficiently in time-domain because its direct incorporation involves a convolution computation. In the present paper, a recently proposed auxiliary differential equations (ADE) method is applied to model the frequency-dependent locally-reacting impedance boundaries as a preliminary of constructing efficient extended-reacting model. The ADE method can reflect frequency-dependent behaviors in time-domain efficiently by solving additional first-order differential equations instead of the convolution computation. Numerical impedance tube problems demonstrate that the present TD-FEM can accurately simulate broadband absorption characteristics of various porous absorbers up to 10 kHz.
    Korean Society of Noise and Vibration Engineering, Aug. 2020, Proceedings of 2020 International Congress on Noise Control Engineering, INTER-NOISE 2020, English
    International conference proceedings

  • Kimihiro Sakagami, Midori Kusaka, Takeshi Okuzono, Shinsuke Nakanishi
    In this study, we discuss the effect of the manufacturing accuracy of a microperforated panel (MPP) produced by 3D printers on acoustic properties through measured and calculated results as a pilot study. The manufacturing costs of MPPs have long been one of their shortcomings; however, with recent developments in the manufacturing process, low-cost MPPs are now available. In a further attempt at reducing the cost, 3D printing techniques have recently been considered. Cases of trial production of MPPs manufactured by 3D printing have been reported. When introducing such new techniques, despite the conventional microdrill procedure, manufacturing accuracy can often become an issue. However, there are few studies reporting the effect of manufacturing accuracy on the acoustic properties in the case of 3D-printed MPPs. Considering this situation, in this pilot study, we attempted to produce MPPs with circular and rectangular perforations using a consumer 3D printer of the additive manufacturing type. The hole sizes of the specimens were measured, and the accuracy was evaluated. The normal incidence absorption coefficient and specific impedance were measured using an impedance tube. The measured results were compared with the theoretical values using Guo’s model. Through these basic studies, the MPPs produced by an additive manufacturing 3D printer demonstrated good sound absorption performance; however, due to the large deviations of parameters, the agreement with the theoretical values was not good, which suggests that it is difficult to predict the acoustic properties of MPPs made by a consumer-grade additive manufacturing 3D printer.
    MDPI AG, Aug. 2020, Acoustics, 2(3) (3), 605 - 616
    [Refereed]
    Scientific journal

  • Jorge P. Arenas, Kimihiro Sakagami
    Technological advances in materials science, manufacturing processes, chemistry and nanoscience have led to enormous developments in innovatively engineered materials over recent decades. Among them, sustainable acoustic materials have helped to improve acoustical comfort in built environments, and their use is rapidly growing in the architecture, automotive, aerospace and construction industries. These materials are manufactured through a responsible interaction with the environment in order to avoid a depletion or degradation of the natural resources, and to allow for long-term environmental quality. This Special Issue reports on some research studies on membrane absorbers and fibrous materials of natural origin that can be sustainable alternatives to traditional acoustic materials.
    Last, MDPI AG, Aug. 2020, Sustainability, 12(16) (16), 6540 - 6540
    [Refereed][Invited]
    Scientific journal

  • Kimihiro Sakagami
    The COVID-19 pandemic caused lockdowns in many countries worldwide. Acousticians have made surveys to monitor how cities became quieter under the lockdown, mainly in central areas in cities. However, there have been few studies on the changes in the acoustic environment due to the pandemic in the usually quieter residential areas. It may be expected to be different from the effect in ‘originally noisy’ areas. Also, the effect could be different in Japan, because the ‘state of emergency’ declaration there was different to lockdowns elsewhere. Considering these circumstances, this article reports the results of noise monitoring and makes some observations on the acoustic environment in residential areas far from city centres, to provide an example of how the acoustic environment was affected by the state of emergency declaration due to the COVID-19 pandemic in Japan. The results showed that the reduction of noise levels was somewhat less than that reported in large cities. Also, comparing the results after the cancellation of the state of emergency, the noise level increased again. However, observations of noise sources imply that a possible change in human behaviour may have also affected the acoustic environment.
    Lead, UCL Press, Aug. 2020, UCL Open Environment, 1(6) (6), English
    [Refereed][Invited]
    Scientific journal

  • Yohei Tsukamoto, Yoshihiro Tomikawa, Kimihiro Sakagami, Takeshi OKuzono, Hidetoshi Maikawa, Yusuke Komoto
    As described herein, the sound insulation performance of a double window with absorbent materials on the perimeter of its cavity is studied experimentally. Two experiments are used to measure the sound reduction indices. The first experiment was performed with a double window composed of commercially available products. The second was conducted with a model constructed of two acrylic panels: a simplified model of a double window with a cavity between the panes. As the result of the first experiment, the improvement in reduction index obtained by the attached absorbent was around 4 dB. In the second experiment, though some negative effect was observed at low frequencies, the increase in reduction index was about 12 dB at maximum. Consequently, the following findings were obtained: (1) Acoustic transmission characteristics of a double window are affected mainly by resonances of two types: mass-air-mass resonance of window panes and the air cavity, and the acoustic mode resonances of the air cavity in-between; (2) acoustic mode resonance is suppressed by attaching absorbent materials on the inside of the cavity of window. Consequently, the sound reduction index increases.
    ELSEVIER, Aug. 2020, Applied Acoustics, 165, 107317, English, International magazine
    [Refereed]
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    Acoustical Society of Japan, Jul. 2020, Acoustical Science and Technology, 41(4) (4), 689 - 692
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Takeshi Okuzono, Hirotaka Suzuki, Nao Koyanagi, Masahiro Toyoda
    The authors propose a space sound absorber made of a permeable membrane (PM), including woven or non-woven fabrics in three-dimensional shapes, e.g., cylinder, rectangle, etc. The proposed absorbers are examined by experimental measurements and boundary element analyses, and it is found that they can be effectively used especially for middle and high frequencies. In order to develop these absorbers for wider applications, it would be desirable to give them additional values and functions, particularly to elaborate on their design. Supposing that they could also be used for lighting equipment, such as lampshades as one of the applications, pilot studies on pseudo-cylindrical, and pseudo-spherical PM space absorbers with uneven surfaces produced by paper-folding (origami technique) are carried out. The pseudo-cylindrical concave curves (PCCC) shell shape has been proven as a suitable form for a lampshade, and the pseudo-spherical concave curves (PSCC) shell shape is an application of PCCC. In this paper, PCCC and PSCC shell shapes are applied to three-dimensional PM space absorbers, and trials are conducted using PMs selected by flow resistance measurements and preliminary simulations. The sound absorptivity of the specimens is measured in a reverberation chamber, and their absorptivity is 0.6 (PCCC case) and 0.4 (PSCC case) at mid-high frequencies.
    INT INST ACOUSTICS & VIBRATION, Jun. 2020, INTERNATIONAL JOURNAL OF ACOUSTICS AND VIBRATION, 25(2) (2), 243 - 247, English
    [Refereed]
    Scientific journal

  • Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    This paper presents a proposal of a time domain room acoustic solver using novel fourth-order accurate explicit time domain finite element method (TD-FEM), with demonstration of its applicability for practical room acoustic problems. Although time domain wave acoustic methods have been extremely attractive in recent years as room acoustic design tools, a computationally efficient solver is demanded to reduce their overly large computational costs for practical applications. Earlier, the authors proposed an efficient room acoustic solver using explicit TD-FEM having fourth-order accuracy in both space and time using low-order discretization techniques. Nevertheless, this conventional method only achieves fourth-order accuracy in time when using only square or cubic elements. That achievement markedly impairs the benefits of FEM with geometrical flexibility. As described herein, that difficulty is solved by construction of a specially designed time-integration method for time discretization. The proposed method can use irregularly shaped elements while maintaining fourth-order accuracy in time without additional computational complexity compared to the conventional method. The dispersion and dissipation characteristics of the proposed method are examined respectively both theoretically and numerically. Moreover, the practicality of the method for solving room acoustic problems at kilohertz frequencies is presented via two numerical examples of acoustic simulations in a rectangular sound field including complex sound diffusers and in a complexly shaped concert hall.
    {MDPI} {AG}, May 2020, Applied Sciences, 10(11) (11), 3750 - 3750, English, International magazine
    [Refereed]
    Scientific journal

  • Takeshi Okuzono, Koji Uenishi, Kimihiro Sakagami
    Permeable membranes (PMs), which are air-permeable fabrics made from various natural or chemical fibers that are thinly woven or non-woven, are attractive sound-absorbing materials. The simplest PM absorber is a single-leaf PM absorber (PMSG) with a non-locally reacting rigid backed air cavity in which a PM is placed in front of a rigidly backed air cavity. A honeycomb-backed single-leaf PM absorber (PMHC), which has a locally reacting air cavity, is also well known. However, the two PM absorbers have shortcomings in their diffuse field absorption coefficients attrib- utable to the backing air cavity design. To overcome those shortcomings, we intro- duce a PM absorber array (PMAR): a single-leaf PM absorber with multiple locally reacting air cavities of different depths. As described herein, to present PMAR benefits, we experimentally compare the diffuse field absorption charac- teristics of the three single-leaf PM absorbers with different air cavity designs. Reverberation absorption coefficient measurements were taken using nine thin permeable membranes made of three chemical fibers, each having different flow resistance and surface density. Results show that PMAR is an effective sound ab- sorbing structure to overcome the shortcomings related to the diffuse field absorp- tion coefficients of PMSG and PMHC. Material property effects on permeable membranes are also demonstrated.
    Institute of Noise Control Engineering (INCE), May 2020, Noise Control Engineering Journal, 68(3) (3), 237 - 245, English, International magazine
    [Refereed]
    Scientific journal

  • Takeshi Okuzono, M Shadi Mohamed, Kimihiro Sakagami
    Predicting room acoustics using wave-based numerical methods has attracted great attention in recent years. Nevertheless, wave-based predictions are generally computationally expensive for room acoustics simulations because of the large dimensions of architectural spaces, the wide audible frequency ranges, the complex boundary conditions, and inherent error properties of numerical methods. Therefore, development of an efficient wave-based room acoustic solver with smaller computational resources is extremely important for practical applications. This paper describes a preliminary study aimed at that development. We discuss the potential of the Partition of Unity Finite Element Method (PUFEM) as a room acoustic solver through the examination with 2D real-scale room acoustic problems. Low-order finite elements enriched by plane waves propagating in various directions are used herein. We examine the PUFEM performance against a standard FEM via two-room acoustic problems in a single room and a coupled room, respectively, including frequency-dependent complex impedance boundaries of Helmholtz resonator type sound absorbers and porous sound absorbers. Results demonstrated that the PUFEM can predict wideband frequency responses accurately under a single coarse mesh with much fewer degrees of freedom than the standard FEM. The reduction reaches O(10^-2) at least, suggesting great potential of PUFEM for use as an efficient room acoustic solver.
    {MDPI} {AG}, Mar. 2020, Applied Sciences, 10(6) (6), 1969 - 1969, English, International magazine, Co-authored internationally
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Fumiaki Satoh, Akira Omoto
    Geo-referenced sound data are often used in the field of acoustics education to learn about the urban acoustic environment. Simple soundwalks and sound collections are also employed, in which acquiring additional information such as visual data, recorded sound data, and GPS location data are helpful to produce a map with sound data and sound collection and to carry out more profound discussions in educational activities. In order to enrich these acoustic educational and environmental survey activities with a simple tool, the use of multifunctional sound-pressure level (SPL) measurement applications with mobile devices are proposed. Some experiences of combined activities of the above methods using the applications and mobile devices are reported in this paper. In this study, applications for SPL measurements, which record GPS location data, sound, photo, and video during measurements, were used to produce geo-referenced sound data. First, the accuracy of the applications was checked and we found them to have reasonable accuracy when used with iOS devices; for example, the averaged error was less than 1.5 dB(A) with iPhone XS. Next, they were actually used in a simple soundwalk-like field survey and the resulting geo-referenced sound data were presented to discuss the merits and demerits of each application. Overall, the applications used in this work were found to be useful; for example, recorded sound allowed us to check the main sound source and to carry out discussions using collected sound samples later, and photos and videos allowed us to grasp the impressions and situations around the measuring points. Therefore, these multifunctional sound level meter (SLM) applications can be effectively used for various purposes, including acoustics education for learning about urban acoustic environments.
    {MDPI} {AG}, Dec. 2019, Urban Science, 3(4) (4), 111 - 111, English
    [Refereed][Invited]
    Scientific journal

  • OKUZONO Takeshi, SAKAGAMI Kimihiro, OTSURU Toru
    This paper presents an overview of the applicability of implicit time-domain FEM (TD-FEM) for room acoustics simulation, which has fourth-order accuracy in both space and time. First, the TD-FEM algorithm is presented with explanations of dispersion-reduced finite elements for spatial discretization and a time integration method for time discretization. The theoretical dispersion error property is also shown. Use of the dispersion-reduced scheme presents benefits in terms of accuracy, stability and convergence of an iterative solver, which have a marked effect on the computational cost. Then, the applicability of TD-FEM is demonstrated using two numerical examples on room acoustics simulation in the kilohertz frequency range, which are acoustics simulations of a simply shaped concert hall and simulation of reverberation absorption coefficient measurements. In numerical examples of concert hall analysis, comparison with a conventional TD-FEM presents the efficiency of the dispersion-reduced TD-FEM. Modeling accuracy of non-locally reacting permeable membrane sound absorbers for the TD-FEM is presented through simulation of reverberation room method.
    Sep. 2019, Proceedings of 23rd International Congress on Acoustics, 6070 - 6077, English, International magazine
    [Refereed]
    International conference proceedings

  • YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    Sep. 2019, Proceedings of 23rd International Congress on Acoustics, 763 - 770, English
    [Refereed]
    Scientific journal

  • OKUZONO TAKESHI, SHIMIZU NORIYASU, SAKAGAMI KIMIHIRO
    Permeable membranes (PMs), which are air-permeable thin woven fabrics or non-woven fabrics, are attractive sound-absorbing materials used to control acoustics in buildings. Although the absorption characteristics of various PM absorbers have been studied extensively, it has not been established how to incorporate PMs into a wave-based acoustic simulation method known as the tim
    Aug. 2019, Applied Acoustics, 151, 172 - 182, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Fumiaki Satoh, Akira Omoto
    In this paper, we revisit the acoustics education program using mobile devices to better understand urban environments. We begin with a summary of our past projects to demonstrate a model case of the concept. In these projects, the output was mainly supposed to be a noise map with measured sound pressure levels (SPLs) and sound spectra. This methodology can obviously be applied
    MDPI (Basel), Jul. 2019, Urban Science, 3(3) (3), 73 - (13 pages), English
    [Refereed]
    Scientific journal

  • Masahiro Toyoda, Kota Funahashi, Takeshi Okuzono, Kimihiro Sakagami
    {MDPI} {AG}, May 2019, Sustainability, 11(9) (9), 2714 - 2714, English
    [Refereed]
    Scientific journal

  • OKUZONO TAKESHI, NITTA TAKAO, SAKAGAMI KIMIHIRO
    May 2019, Acoustical Science and Technology, 40(3) (3), 221 - 224, English
    [Refereed]
    Scientific journal

  • SAKAGAMI KIMIHIRO, OKUZONO TAKESHI, SOMATOMO YU, FUNAHASHI KOTA, TOYODA MASAHIRO
    Apr. 2019, Sustainability, 11(7) (7), 2185, English
    [Refereed]
    Scientific journal

  • Asniawaty Kusno, SAKAGAMI KIMIHIRO, OKUZONO TAKESHI, TOYODA MASAHIRO, OTSURU TORU, Rosady Mulyadi, Kusno Kamil
    Mar. 2019, Sustainability, 11(5) (5), 1476, English
    [Refereed]
    Scientific journal

  • TAKAHASHI KATSUTOSHI, YAIRI MOTOKI, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO, TOYODA MASAHIRO
    Jan. 2019, Acoustical Science and Technology, 40(1) (1), 52 - 55, English
    [Refereed]
    Scientific journal

  • Yairi Motoki, Sakagami Kimihiro, Okuzono Takeshi
    2019, ACOUSTICAL SCIENCE AND TECHNOLOGY, 40(5) (5), 325 - 335
    [Refereed]

  • Hoshi Kazuma, Hanyu Toshiki, Okuzono Takeshi, Sakagami Kimihiro, Yairi Motoki, Harada Shinji, Takahashi Seiji, Ueda Yasutaka
    Jan. 2019, APPLIED ACOUSTICS, 157
    [Refereed]

  • OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    Sep. 2018, Acoustical Science and Technology, 39(5) (5), 362 - 365, English
    [Refereed]
    Scientific journal

  • RELATIONSHIP BETWEEN SOUND RADIATION FROM SOUND-INDUCED AND FORCE-EXCITED VIBRATION
    YAIRI Motoki, SAKAGAMI Kimihiro, OKUZONO Takeshi
    Jul. 2018, Proc of 25th Internaltional Congress on Sound and Vibration, No.287, 1 - 8, English
    [Refereed][Invited]
    International conference proceedings

  • IMPLEMENTATION EXPERIMENT OF A HONEYCOMB-BACKED MPP SOUND ABSORBING PANEL IN A MEETING ROOM
    HOSHI Kazuma, HANYUToshiki, SAKAGAMI Kimihiro, OKUZONO Takeshi, YAIRI Motoki, HARADA Shinji, TAKAHASHI Seiji, UEDA Yasutaka
    Jul. 2018, Proc of 25th Internaltional Congress on Sound and Vibration, No.1049, 1 - 8, English
    [Refereed][Invited]
    International conference proceedings

  • A THREE-DIMENSIONAL TIME-DOMAIN FINITE ELEMENT METHOD BASED ON FIRST-ORDER ORDINARY DIFFERENTIAL EQUATIONS FOR TREATING PERMEABLE MEMBRANE ABSORBERS
    YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    Jul. 2018, Proc of 25th Internaltional Congress on Sound and Vibration, No.838, 1 - 7, English
    [Refereed]
    International conference proceedings

  • AN EXPERIMANTAL STUDY ON THE ABSORPTION CHARACTERISTICS OF PERMEABLE MEMBRANE ABSORBERS ARRAY
    OKUZONO Takeshi, UENISHI Koji, SAKAGAMI Kimihiro, SHIMIZU Hikaru
    Jul. 2018, Proc of 25th Internaltional Congress on Sound and Vibration, No.48, 1 - 6, English
    [Refereed][Invited]
    International conference proceedings

  • YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    May 2018, Noise Control Engineering Journal, 66(3) (3), 176 - 189, English
    [Refereed]
    Scientific journal

  • Relation between sound radiation from airborne-sound and point-force excitations of a double-leaf plate
    Motoki Yairi, Kimihiro Sakagami, Takeshi Okuzono
    An expanded theory for relating airborne-sound-excited and force-excited sound radiation from solid structures is presented. Although reduction of these two types of sound radiation is a fundamental issue in noise-control engineering, each of them has been treated as separate issues. A previous study established a fundamental relationship between the sound radiation from airborne-sound-excited and force-excited vibration of a single-leaf plate. A conversion function that relates the two excitation cases was presented in a simple closed-form, not including the plate’s parameters. In this paper, the applicability of the conversion function is expanded from a single-leaf infinite elastic plate model to a double-leaf plate model.
    Institute of Noise Control Engineering, 2018, INTER-NOISE 2018 - 47th International Congress and Exposition on Noise Control Engineering: Impact of Noise Control Engineering, English
    International conference proceedings

  • Takeshi Okuzono, Kimihiro Sakagami
    Microperforated panel (MPP) absorbers, which provide broadband sound absorption without the use of fibrous materials, have favorable material properties that support recyclability, flexibility of design, hygiene demands, and cleaning. Many earlier studies have specifically examined the development of absorbers themselves. However, to use the absorption performance of MPP absorbers sufficiently in room acoustic applications, it is beneficial to develop accurate prediction methods of sound fields in rooms with MPP absorbers. Such methods are expected to be useful for room acoustics design and absorber design tools. This study constructs a frequency domain finite element (FE) solver for acoustic simulations of a practical sized room with MPP absorbers. Then the accuracy and effectiveness are evaluated. In the FE solver, spatial domains are discretized by fourth-order accurate FEs in terms of dispersion error, and MPP absorbers are modeled using first-order hexahedral limp MPP elements that can deal with sound propagation in the backing structure of absorbers. First, the accuracy of present FE solver is demonstrated using impedance tube problems in comparison with conventional second-order accurate FEs. Results show higher convergence of solutions for the present FE solver. Then, exploration of an iterative solver for efficient multi-frequency analyses reveals that the recently developed CSQMOR is a faster and more stable solver. Finally, comparison with a conventional surface impedance model based on a locally reacting assumption confirms the effectiveness of present FE solver by presenting the importance of dealing with the incident angle dependence of reactance of a rigid-backed air cavity in the modeling of single leaf MPP absorbers. (C) 2017 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Jan. 2018, APPLIED ACOUSTICS, 129, 1 - 12, English
    [Refereed]
    Scientific journal

  • A first-order ODE based explicit time-domain FEM for room acoustic simulations
    OKUZONO Takeshi, YOSHIDA Takumi, SAKAGAMI Kimihiro
    Aug. 2017, Proc of inter.noise2017, 371 - 379, English
    [Refereed][Invited]
    International conference proceedings

  • An implicit time-domain finite element scheme for sound field analysis with permeable membrane absorbers
    OKUZONO Takeshi, SAKAGAMI Kimihiro, KATSUYAMA Akihiro
    Jul. 2017, Proc of 24th Internaltional Congress on Sound and Vibration, NO.961, 1 - 8, English
    [Refereed][Invited]
    International conference proceedings

  • Chicken feather: An alternative of acoustical materials
    Asniawaty Kusno, Masahiro Toyoda, Kimihiro Sakagami, Takeshi Okuzono, Toru Otsuru, Kusno Kamil, Vovi Masgode
    Researchers' contributions on green materials development for sound insulation are increas-ingly in demand, including the abundant wasted chicken feathers. This study examines possi-bility of chicken feathers (CF) as an alternative acoustical material through understanding of its sound absorption characteristics. Common absorptive material glass wool (GW) applies as counterpart in measurements. Clean and dried CF is compacted in mesh prior to absorption coefficient measurement. Acoustical measurements by EA method were applied on typical thickness CF specimen of 48 and 60 kg/cm3 mesh densities. Specimen respond of absorption coefficient are relatively increase throughout frequency ranges of 100-1600 Hz, reaching maximum 0.99 at frequency 1600 Hz, 950 Hz, and 650 Hz for CF thickness 25, 50 and 75 mm, respectively. Measurement confirmation on glass wool (GW) specimen was resulted in comparable results. Flow resistivity test is applied for empirical model confirmation, resulted in diverged phenomenon and improperly fix to Miki's model as the common empirical model of fibrous acoustic materials. More measurements with variation on specimen densities should validate the possibility of chicken feathers as potential alternative of acoustical materials.
    International Institute of Acoustics and Vibration, IIAV, 2017, 24th International Congress on Sound and Vibration, ICSV 2017, English
    International conference proceedings

  • Emi Toyoda, Takeshi Okuzono, Mitsuru Okano, Kimihiro Sakagami, Masahiro Toyoda
    Because microperforated panels (MPPs), which can be made from various materials, provide wide-band sound absorption, they are recognized as one of the next-generation absorption materials. Although MPPs are typically placed in front of rigid walls, MPP space sound absorbers without a backing structure, including three-dimensional cylindrical MPP space absorbers (CMSAs) and rectangular MPP space absorbers (RMSAs), are proposed to extend their design flexibility and easy-to-use properties. On the other hand, improving the absorption performance by filling the back cavity of typical MPP absorbers with porous materials has been shown theoretically, and three-dimensional MPP space absorbers should display similar improvements. Herein the effects of porous materials inserted into the cavities of CMSA5 and RMSAs are experimentally investigated and a numerical prediction method using the two-dimensional boundary element method is proposed. Consequently, CMSA5 and RMSAs with improved absorption performances are illustrated based on the experimental results, and the applicability of the proposed prediction method as a design tool is confirmed by comparing the experimental and numerical results. (C) 2016 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Jan. 2017, Applied Acoustics, 116, 311 - 316, English
    [Refereed]
    Scientific journal

  • Koji Uenishi, Takeshi Okuzono, Kimihiro Sakagami
    Acoustical Society of Japan, 2017, Acoustical Science and Technology, 38(6) (6), 322 - 325, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Fumiaki Satoh, Akira Omoto
    In order to propose an effective method using smartphones (including tablets) for acoustics education in introductory courses for architectural and environmental acoustics for architectural studies, the authors have examined some applications which work on smartphones. As the first step applications measuring sound level and spectrum at reasonable prices are chosen and their precisions have been verified. Results showed that the most iOS devices have somewhat reasonable precision, e.g., for SPL measurement it is similar to Class 2 sound level meter, though some Android devices give lower precision. Then the authors introduced these tools to students and encouraged them to use these tools to produce a noise map (with dB(A) only and with both dB(A) and sound spectra). Even though these are only simple tools, they allow students to understand the relationship between their sensation and physical values. As further studies, the authors also tried to use some more applications which enable students to measure more advanced physical values, such as Band Levels, Leq, Impulse Responses, Reverberation Times etc. Some examples of the measurement results of them are also presented.
    Acoustical Society of America, Nov. 2016, Proceedings of Meetings on Acoustics, 29(1) (1), English
    [Refereed][Invited]
    International conference proceedings

  • 通気性膜を用いた立体型空間吸音体の吸音特性の3次元境界要素解析
    FUNAHASHI Kouta, TOYODA Masahiro, SAKAGAMI Kimihiro, OKUZONO Takeshi
    日本音響学会, Jul. 2016, 日本音響学会誌, 72(7) (7), 383 - 385, Japanese
    [Refereed]
    Scientific journal

  • 長方形要素を用いた陽的時間領域有限要素法による室内音場解析のための修正積分則
    YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会, Jul. 2016, 日本音響学会誌, 72(7) (7), 367 - 373, Japanese
    [Refereed]
    Scientific journal

  • Motoki Yairi, Kimihiro Sakagami, Kosuke Nishibara, Takeshi Okuzono
    Although sound radiation from sound-induced vibration and from force-excited vibration of solid structures are similar phenomena in terms of radiating from vibrating structures, the general relationship between them has not been explicitly studied to date. In particular, airborne sound transmission through walls and sound radiation from structurally vibrating surfaces in buildings are treated as different issues in architectural acoustics. In this paper, a fundamental relationship is elucidated through the use of a simple model. The transmission coefficient for random-incidence sound and the radiated sound power under point force excitation of an infinite elastic plate are both analyzed. Exact and approximate solutions are derived for the two problems, and the relationship between them is theoretically discussed. A conversion function that relates the transmission coefficient and radiated sound power is obtained in a simple closed form through the approximate solutions. The exact solutions are also related by the same conversion function. It is composed of the specific impedance and the wavenumber, and is independent of any elastic plate parameters. The sound radiation due to random-incidence sound and point force excitation are similar phenomena, and the only difference is the gradient of those characteristics with respect to the frequency. (C) 2016 Acoustical Society of America.
    ACOUSTICAL SOC AMER AMER INST PHYSICS, Jul. 2016, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, 140(1) (1), 453 - 460, English
    [Refereed]
    Scientific journal

  • Takeshi Okuzono, Takumi Yoshida, Kimihiro Sakagami, Toru Otsuru
    This paper presents the applicability of an explicit time-domain finite element method (TD-FEM) using a dispersion reduction technique called modified integration rules (MIR) on room acoustics simulations with a frequency-independent finite impedance boundary. First, a dispersion error analysis and a stability analysis are performed to derive the dispersion relation and the stability condition of the present explicit TD-FEM for three-dimensional room acoustics simulations with an infinite impedance boundary. Secondly, the accuracy and efficiency of the explicit TD-FEM are presented by comparing with implicit TD-FEM using MIR through room acoustics simulations in a rectangular room with infinite impedance boundaries. Thirdly, the stability condition of the explicit TD-FEM is investigated numerically in the case with finite impedance boundaries. Finally, the performance of the explicit TD-FEM in room acoustics simulations with finite impedance boundaries is demonstrated in a comparison with the implicit TD-FEM. Although the stability of the present explicit TD-FEM is dependent on the impedance values given at boundaries, the explicit TD-FEM is computationally more efficient than the implicit method from the perspective of computational time for acoustics simulations of a room with larger impedance values at boundaries. (c) 2015 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Mar. 2016, APPLIED ACOUSTICS, 104, 76 - 84, English
    [Refereed]
    Scientific journal

  • A note on the relationship between airborne sound transmission and structure-borne sound radiation: Basic study using classical approximate solution for a single-leaf elastic plate
    YAIRI MOTOKI, SAKAGAMI KIMIHIRO, OKUZONO TAKESHI, NISHIBARA KOSUKE
    日本音響学会, Feb. 2016, Journal of the Acoustical Society of Japan (J), 72(2) (2), 68 - 72, Japanese
    [Refereed]
    Scientific journal

  • Takeshi Okuzono, Kimihiro Sakagami
    Acoustical Society of Japan, 2016, Acoustical Science and Technology, 37(1) (1), 46 - 49, English
    [Refereed]
    Scientific journal

  • Fumiaki Satoh, Kimihiro Sakagami, Akira Omoto
    In an introductory course for environmental/architectural acoustics in universities, it is often used the teaching method based on soundscape, in which students are asked to make a sound map with listening their surrounding acoustic environment. However, if objective measurement of sound pressure level or frequency spectrum can be introduced in such a course, it will interest students in environmental acoustics, and enable them to discuss the acoustic environment more profoundly. Measurement apparatuses are usually expensive and difficult to be used in such a course. Therefore, we consider to use a smartphone: using a smartphone with acoustic measurement applications, it can be possible to introduce an objective measurement in such an introductory course for beginners. In this study, first some applications for acoustic measurement are examined to confirm their accuracy as well as the effect of a simple handmade windscreen. Secondly, using suitable applications, as a possible work in the course, sound maps with measurement results by a smartphone are made and their examples are shown. Finally, some issues to introduce this method in actual courses are discussed.
    Acoustical Society of Japan, 2016, Acoustical Science and Technology, 37(4) (4), 165 - 172, English
    [Refereed]
    Scientific journal

  • Three-dimensional MPP and permeable membrane space sound absorbers: An overview
    SAKAGAMI KIMIHIRO, OKUZONO TAKESHI, YAIRI MOTOKI, TOYODA MASAHIRO
    WESPAC, Dec. 2015, Proceedings of 12th WESPAC, English
    [Refereed][Invited]
    International conference proceedings

  • Masahiro Toyoda, Shota Fujita, Kimihiro Sakagami
    Microperforated panels (MPPs) are next-generation absorption materials because they can provide wideband sound absorption without fibrous materials and can be composed of diverse materials to meet global environmental demands. The fundamental absorbing mechanism is Helmholtz-resonance absorption due to perforations and an air cavity. MPPs are typically backed by rigid flat walls, but to reduce the restrictions on the MPP absorber properties, one of the authors has proposed MPP space sound absorbers without backing structures, including three-dimensional cylindrical microperforated panel space absorbers (CMSAs). Advantages of MPPs without backing structures are design flexibility and ease of use. Besides, the absorption characteristics of a CMSA with a core, which has a rigid cylindrical core inside the CMSA, have been experimentally tested, but a method to predict the absorption characteristics is necessary to design CMSAs with cores. Herein the two-dimensional combined Helmholtz integral formulation method is employed, and its prediction accuracy is evaluated by comparing the measured and predicted absorption characteristics of a CMSA with a core. Furthermore, a parametric study with regard to the core size is carried out to investigate the transition of the absorbing mechanism. (C) 2015 Acoustical Society of America.
    ACOUSTICAL SOC AMER AMER INST PHYSICS, Dec. 2015, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, 138(6) (6), 3531 - 3538, English
    [Refereed]
    Scientific journal

  • A comparison of absorption models of microperforated panel absorbers on room acoustics simulations using finite element method
    OKUZONO Takeshi, SAKAGAMI Kimihiro
    Dec. 2015, Proc of 12th Wespac, No.O4000037, 63 - 66, English
    [Refereed]
    International conference proceedings

  • On the relationship between the normal incidence airborne sound-excited and the structurally-excited sound radiation from a wall: A theoretical trial with simplified models
    YAIRI MOTOKI, SAKAGAMI KIMIHIRO, NISHIBARA KOSUKE, OKUZONO TAKESHI
    Multi-Science Publishing, Oct. 2015, Journal of Building Acoustics, 22(2) (2), 109 - 122, English
    [Refereed]
    Scientific journal

  • SAKAGAMI KIMIHIRO
    Arpa Press, Aug. 2015, International Journal of Reseach and Reviews in Applied Sciences, 24(2) (2), 59 - 66, English
    [Refereed]
    Scientific journal

  • Takeshi Okuzono, Kimihiro Sakagami
    A simple frequency-domain finite-element method (FD-FEM) for sound field analyses inside rooms installed with microperforated panel (MPP) sound absorbing structures is described here. This method can also analyze sound absorbing structures composed of MPPs and permeable membranes (PM) simply by changing the only material parameters of MPP into those of PM. As the first stage of the study, the validity of the present FD-FEM is tested through the numerical experiments based on the impedance tube method for measuring the absorption characteristics at normal incidence. In the numerical experiments, we calculated the absorption characteristics of a single MPP absorber, a double-leaf MPP space absorber and a space absorber composed of MPP and PM by using the FD-FEM in two-dimensions, and the computed absorption characteristics are compared with those calculated by an electro-acoustical equivalent circuit theory or a wave theory based on Helmholtz-Kirchhoff boundary integral equation. The results showed that the presented FD-FEM can analyze the absorption characteristics at normal incidence of the MPP sound absorbing structures accurately with the simplicity of the formulation. (C) 2015 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Aug. 2015, APPLIED ACOUSTICS, 95, 20 - 26, English
    [Refereed]
    Scientific journal

  • 通気性単一膜を用いた矩形平面状空間吸音体の残響室法吸音率測定
    SOMATOMO YU, OKUZONO TAKESHI, FUNAHASHI KOTA, SAKAGAMI KIMIHIRO, TOYODA MASAHIRO
    日本音響学会, Jun. 2015, 日本音響学会誌, 71(6) (6), 276 - 277, Japanese
    [Refereed]
    Scientific journal

  • An experimental study on the absorption characteristics of a three-dimensional permeable membrane space sound absorber
    Kimihiro Sakagami, Kota Funahashi, Yu Somatomo, Takeshi Okuzono, Chinami Nishikawa, Masahiro Toyoda
    In this study, we propose a rectangular and cylindrical three-dimensional space sound absorber using a permeable membrane and the absorption characteristics which are examined experimentally by reverberation room method. As a pilot study, a two-dimensional boundary element (2-D BEM) analysis is also conducted to predict the absorption characteristics of the absorbers. The experimental study revealed that the absorption coefficient is low at low frequencies and gradually increases with frequency. The absorption coefficient converges to 0.5 at the maximum which is similar to a single-leaf permeable membrane. The flow resistance and the surface density of the permeable membrane mainly affect the absorption characteristics at middle to high frequencies. At low frequencies, the heavy membrane contributes to the higher absorption performance. In the experiment specimens with high flow resistance produce higher absorptivity. Also, the cylindrical absorber shows slightly higher absorption coefficient than the rectangular absorber mainly at low frequencies. The 2-D BEM results show similar frequency characteristics as the measured values when the membrane's flow resistance and surface density are low, but the numerical values overestimate overall the absorptivity of the absorbers. (C) 2015 Institute of Noise Control Engineering.
    INST NOISE CONTROL ENGINEERING, May 2015, NOISE CONTROL ENGINEERING JOURNAL, 63(3) (3), 300 - 307, English
    [Refereed]
    Scientific journal

  • An experimental study on the sound transmission characteristics of a panel for spherical sound wave incidence
    YAIRI MOTOKI, TSUKAMOTO YOHEI, SAKAGAMI KIMIHIRO
    Kobe University, Mar. 2015, Memoirs of the Graduate School of Engineering and System Informatics, Kobe University, (6) (6), 1 - 5, Japanese
    [Refereed]
    Research institution

  • MITSURU OKANO, SAKAGAMI KIMIHIRO, MOTOKI YAIRI
    Kobe University, Mar. 2015, Memoirs of the Graduate School of Engineering and System Informatics Kobe University, 6(6) (6), 7 - 12, English
    [Refereed]
    Research institution

  • Takeshi Okuzono, Kimihiro Sakagami
    The authors proposed a simple finite element (FE) formulation in order to predict sound fields in rooms with microperforated panel (MPP) absorbers, and its validity was also presented through comparisons with electro acoustical equivalent circuit theory and wave theory in numerical experiments based on an impedance tube method. A 2D room acoustics simulation with a single-leaf MPP absorber is performed, in which a surface impedance model based on a locally reactive assumption is also used for comparison. This model uses the normal-incidence normalized acoustic impedance on the surface of the MPP absorber under an impedance boundary condition based on the locally reactive assumption that neglects the incident-angle dependence of the normalized acoustic impedance. The results are compared with results obtained without the single-leaf MPP absorber in the 1/3-octave-band mean sound pressure level (SPL) and in the 1/3-octave-band SPL distribution. From the results, it is expected that the reduction effect of the SPL after installing the single-leaf MPP absorber will be overestimated overall when using the surface impedance model.
    Acoustical Society of Japan, 2015, Acoustical Science and Technology, 36(4) (4), 358 - 361, English
    [Refereed]
    Scientific journal

  • Takeshi Okuzono, Toru Otsuru, Kimihiro Sakagami
    The accuracy and efficiency of the explicit time-domain finite-element method (TD-FEM) was studied with the dissipation term on room acoustics simulation at high frequencies through a numerical comparison with the implicit TD-FEM for large-scale analysis. Sound fields inside the cubic cavity with finite impedance boundaries were computed to reveal the effect of the use of the backward difference in the dissipation term of the explicit method on the resulting accuracy in analysis at high frequencies. Computed sound pressures were compared with the reference solution obtained using the implicit method. In the computations, the time interval of the explicit method was again determined by the stability condition of the implicit method and was set to near the critical value. It can be said that this method is very useful for room acoustics simulation, in which the room shape can be approximated by cubic FEs. The applicability of the explicit method for more generalized cases using rectangular FEs and distorted FEs will be presented in the future, as well as derivations of dispersion relation and stability condition for three-dimensional analysis.
    Acoustical Society of Japan, 2015, Acoustical Science and Technology, 36(4) (4), 377 - 380, English
    [Refereed]
    Scientific journal

  • 立体型MPP空間吸音体の吸音特性予測
    TOYODA MASAHIRO, FUJITA SHOTA, KOBATAKE SEIJI, SAKAGAMI KIMIHIRO
    関西大学, Jan. 2015, 第19回関西大学先端科学技術シンポジウム論文集, 281 - 286, Japanese
    [Invited]
    Symposium

  • A SIMPLE FREQUENCY DOMAIN FINITE-ELEMENT FORMULATION FOR PREDICTING ABSORPTION CHARACTERISTICS OF MICROPERFORATED PANEL ABSORBERS
    Takeshi Okuzono, Kimihiro Sakagami
    Sound-absorbing materials play an important role in the control of acoustics in built environments. Recently, the concept of sustainable acoustical materials is becoming important in the development of sound-absorbing materials. Microperforated panels (MPP) that can be made from any recyclable materials are one of such materials. Various MPP absorbers and prediction methods of their absorption characteristics have been proposed. Wave-based numerical methods such as the finite-element method (FEM) are one of the powerful tools to design MPP absorbers. In this paper, first, we present a simple and computationally-efficient frequency-domain FEM for predicting absorption characteristics of MPP absorbers, in which only two material parameters, MPP's acoustic impedance determined by Maa's theory and MPP's surface density, are used. Then, the effectiveness of the present FEM is tested through numerical experiments based on an impedance tube method for measuring sound absorption characteristics at normal incidence. In the numerical experiments, we calculated absorption characteristics of a single MPP absorber, a double-leaf MPP space absorber, and a space absorber composed of MPP and permeable membranes (PM), respectively, using the FEM. The results calculated using the FEM are verified by comparison with absorption characteristics calculated using electro-acoustical equivalent circuit theory and wave theory based on Helmholtz-Kirchhoff boundary integral equation. The numerical experiments revealed that the present FEM can be analyzed normal incidence sound absorption characteristics of MPP absorbers composed of MPP and PM, accurately, within the application range of the formulation.
    INT INST ACOUSTICS & VIBRATION, 2015, PROCEEDINGS OF THE 22ND INTERNATIONAL CONGRESS ON SOUND AND VIBRATION, 1 - 8, English
    [Refereed][Invited]
    International conference proceedings

  • K. Funahashi, Y. Somatomo, C. Nishikawa, K. Sakagami, T. Okuzono, M. Toyoda
    Due to limitations of computes, prediction of structure-borne sound remain difficult for large-scale problems. Herein a prediction method for low-frequency structure-borne sound transmissions on concrete structures using the finite-difference time-domain scheme is proposed. The target structure is modeled as a composition of multiple plate elements to reduce the dimensions of the simulated vibration field from three-dimensional discretization by solid elements to two-dimensional discretization. This scheme reduces both the calculation time and the amount of required memory. To validate the proposed method, the vibration characteristics using the numerical results of the proposed scheme are compared to those measured for a two-level concrete structure. Comparison of the measured and simulated results suggests that the proposed method can be used to simulate real-scale structures.
    The Japan Society of Mechanical Engineers, Dec. 2014, Journal of the Acoustical Society of America, 6, 18 - 21, English
    [Refereed]
    Scientific journal

  • An explicit time-domain finite-element method for room acoustics simulation
    OKUZONO Takeshi, OTSURU Toru, SAKAGAMI Kimihiro
    Nov. 2014, CD-ROM Proceedings of inter.noise 2014, English
    [Refereed][Invited]
    International conference proceedings

  • Prediction method for absorption characteristics of three-dimensional MPP space absorbers
    TOYODA MASAHIRO, FUJITA SHOTA, KOBATAKE SEIJI, SAKAGAMI KIMIHIRO
    European Association of Acoustics, Sep. 2014, Proceedings of Forum Acusticum (CD-ROM), English
    [Refereed][Invited]
    Scientific journal

  • Utilization of smartphones for teaching introductory architectural/environmental acoustics: Examinations of applications and an example of sound map
    SATOH FUMIAKI, SAKAGAMI KIMIHIRO, OMOTO AKIRA
    大学初年級における音環境導入教育においては,環境で聞いた音をサウンドマップにまとめるなどのサウンドスケープ的手法が取られることが多く,考察は定性的かつ主観的なものにとどまることになる。しかし,客観的な物理量を測定して定量的に考察を進めることも重要である。一方,近年のスマートフォンの普及はめざましく,多数の音響分析アプリケーションもある。本稿では,これらを音環境の導入教育へ利用することを想定し,測定値の精度の検証を行った上で実際の音環境導入教育において考えうるサウンドマップ作成の課題についてその作例を示し,スマートフォンを利用した音環境導入教育への試案について今後の課題を示した。
    Acoustical Society of Japan, May 2014, Journal of the Acoustical Society of Japan, 70(5) (5), 260 - 265, Japanese
    [Refereed]
    Scientific journal

  • Numerical analyses of the sound absorption of three-dimensional MPP space sound absorbers
    TOYODA MASAHIRO, KOBATAKE SEIJI, SAKAGAMI KIMIHIRO
    Elsevier, Feb. 2014, Applied Acoustics, 79, 69 - 74, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Tomohito Nakamori, Masayuki Morimoto
    A theoretical study was conducted to investigate triple-leaf microperforated panel absorbers. The addition of an extra microperforated panel (MPP) leaf to a double-leaf MPP space sound absorber (DLMPP), and a triple-leaf MPP space sound absorber (TLMPP) were considered to propose more efficient MPP space sound absorber. The method of analyses for a TLMPP was similar to that for a DLMPP and the formulation was obtained by extending the theory by adding the equations relating to the third MPP leaf. The theoretical analysis was made in the case of the normal incidence of a plane wave, as this study intended to clarify the fundamental feature of a TLMPP. The surface pressures of the illuminated side and the back side of each MPP leaf were expressed by wave theory.
    Acoustical Society of Japan, 2014, Acoustical Science and Technology, 35(2) (2), 122 - 124, English
    [Refereed]
    Scientific journal

  • Motoki Yairi, Takashi Koga, Kenichi Takebayashi, Kimihiro Sakagami
    This paper examines the sound insulation of a single-leaf wall driven by a spherical wave. The transmitted sound field of an infinite elastic plate under a spherical wave incidence is theoretically analyzed and insulation mechanisms are considered. The displacement of the plate is formulated using the Hankel transform in wavenumber space and the transmitted sound pressure in the far-field is obtained by Rayleigh's formula in an explicit closed form. Moreover, a reduction index is also derived in a closed form by introducing an approximation into the vibration characteristics of the plate. Deterioration of the insulation performance under the spherical wave incidence is caused by an apparent decrease of wall impedance that depends on the directivity of the transmitted sound wave. The mass law for a spherical wave incidence is different from that for a normal plane wave incidence: doubling the weight of the wall or the frequency gives an increase of 3 dB (c.f. 6 dB for a normal plane wave incidence), which is also smaller than the field incidence mass law. © 2013 Elsevier Ltd. All rights reserved.
    Elsevier, 2014, Applied Acoustics, 75(1) (1), 67 - 71, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Yusaku Fukutani, Motoki Yairi, Masayuki Morimoto
    As for the sound absorbing system using an MPP (microperforated panel), a double-leaf MPP sound absorber has been studied so far. However, this structure uses two MPPs, which are still expensive, and is disadvantageous when its cost is concerned. Therefore, it is considered that it can be advantageous if one of the leaves can be replaced with a less expensive material keeping high sound absorption performance. In this study, the possibility of producing a useful sound absorbing structure with an MPP and a permeable membrane as an alternative less expensive material is examined. The acoustic properties of this MPP and permeable membrane combination absorber are analysed theoretically with a Helmholtz integral formulation. The absorption performance and mechanism are discussed through the numerical examples. Also, the effect of a honeycomb in the air cavity, which is to be used for reinforcing the structure, is also discussed through a theoretical analysis. © 2013 The Authors. Published by Elsevier Ltd. All rights reserved.
    Elsevier, 2014, Applied Acoustics, 76, 28 - 34, English
    [Refereed]
    Scientific journal

  • FUNAHASHI Kota, SOMATOMO Yu, NISHIKAWA Chinami, SAKAGAMI Kimihiro, OKUZONO Takeshi, TOYODA Masahiro
    神戸大学大学院工学研究科, 2014, 神戸大学大学院工学研究科・システム情報学研究科紀要, 6(6) (6), 17 - 23, Japanese
    [Refereed]
    Research institution

  • A theoretical study on the effect of a permeable membrane in the air cavity of a double-leaf microperforated panel space sound absorber
    SAKAGAMI KIMIHIRO, FUKUTANI YUSAKU, YAIRI MOTOKI, MORIMOTO MASAYUKI
    Elsevier, Dec. 2013, Applied Acoustics, 79, 104 - 109, English
    [Refereed]
    Scientific journal

  • An experimental study of a cylindrical microperforated panel sound absorber with core
    FUJITA SHOTA, SAKAGAMI KIMIHIRO, YAIRI MOTOKI, TOYODA EMI, MORIMOTO MASAYUKI
    Institute of Noise Control Engineering, USA, Dec. 2013, Noise Control Engineering Journal, 61(6) (6), 590 - 596, English
    [Refereed]
    Scientific journal

  • AN EXPERIMENTAL STUDY ON THE SOUND ABSORPTION OF THREE-DIMENSIONAL MPP SPACE SOUND ABSORBERS: RECTANGULAR MPP SPACE SOUND ABSORBER (RMSA)
    Kimihiro Sakagami, Motoki Yairi, Emi Toyoda, Masahiro Toyoda
    A microperforated panel (MPP) is usually placed with a rigid-back wall to form a Helmholtz resonator with its hole and the air-back cavity. However, the authors have so far proposed an MPP space sound absorber without any backing structure. In the previous studies, as a basic form of such an MPP space absorber, multiple-leaf MPP structures without a back wall were proposed, and were theoretically and experimentally examined. In order to provide more unrestricted usage and designs for an MPP space absorber, the authors have also proposed a three-dimensional MPP space absorber, called a cylindrical MPP space absorber (CMSA). The CMSA was shown to exhibit resonance peak absorption and additional low frequency absorption. In this paper, another alternative of a three-dimensional MPP space absorber, a rectangular MPP space absorber (RMSA) is proposed. Its sound absorption performance is discussed using experimentally measured results. The results show sound absorption characteristics similar to a CMSA, and an RMSA can be effectively used if properly designed.
    AUSTRALIAN ACOUSTICAL SOC, Aug. 2013, ACOUSTICS AUSTRALIA, 41(2) (2), 156 - 159, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Fumiaki Satoh, Akira Omoto
    A case study of introductory teaching method for architectural or environmental acoustics using a smartphone is discussed. The results of a trial exercise to make a sound map with the physical measurement results by a smartphone assigned to the students are examined in this case study. The trial exercise is supposed to be a possible assignment in the introductory course on environmental acoustics in the first or second year students of university. It has been in the preliminary study that Android smartphones show large scatter in the measured results of sound pressure levels regardless of which applications are used. Investigations also reveal that devices using iOS do not show such a scatter but, the measured results are all in good agreement. The findings of the study reveal that devices using iOS are suitable for the purpose of the existing case study.
    日本音響学会, 2013, Acoustical Science and Technology, 34(3) (3), 209 - 211, English
    [Refereed]
    Scientific journal

  • Experimental identification of force radiation modes
    Zenzo Yamaguchi, Kimihiro Sakagami, Masayuki Morimoto, J. Stuart Bolton
    The location of a vibration source within a machine is sometimes found to have a significant impact upon the machine's radiated sound power. Radiation mode analysis is known to be a powerful tool for interpreting and predicting sound radiation from a vibrating object since radiation modes are independent of a structure's surface vibration. However, knowledge of the radiation modes alone cannot be used directly to understand the relationship between vibration source location and sound power radiation. Previously, it was suggested that the radiation mode concept could be extended to understand the relationship between the sound power and the driving force distribution by combining a structure's mobility matrix and its radiation modes to form force radiation modes (f(rad)-modes). It was demonstrated by simulation that the radiated sound power can be reduced by choosing the driving force location to be at or near the nodes of the force radiation modes. Here, to further validate the usefulness of the force radiation mode concept, the acoustic transfer vectors and the mobility matrix of a thin steel strip mounted in a rigid baffle were first measured. Then, the force radiation modes were calculated by using the experimental data and it was confirmed that the force radiation modes can serve as a practical guide for choosing a vibration source location that minimizes the radiated sound power, especially at low frequencies. (C) 2012 Institute of Noise Control Engineering.
    INST NOISE CONTROL ENGINEERING, Jan. 2013, NOISE CONTROL ENGINEERING JOURNAL, 61(1) (1), 81 - 86, English
    [Refereed]
    Scientific journal

  • Reduction of sound radiation by using force radiation modes: effect of a rigid wall near a vibration object
    YAMAGUCHI ZENZO, ISHIBASHI SHINJI, SAKAGAMI KIMIHIRO, MORIMOTO MASAYUKI, BOLTON J, STUART
    Aug. 2012, CD-ROM Proceedings of Inter-Noise 2012, English
    International conference proceedings

  • Sound absorption structures including a microperforated panel, permeable membrane and porous absorbent: An overview
    SAKAGAMI KIMIHIRO, MORIMOTO MASAYUKI
    May 2012, Proceedings of the 5th IBPC, 1127 - 1131, English
    [Refereed]
    International conference proceedings

  • A case study of introductory teaching method for environmental and architectural acoustics in universities using a smartphone: An examination of applications and an example of sound map
    SAKAGAMI KIMIHIRO, SATOH FUMIAKI, OMOTO AKIRA
    Kobe University, 2012, MEMOIRS OF THE GRADUATE SCHOOLS OF ENGINEERING AND SYSTEM INFORMATICS, KOBE UNIVERSITY, 4(4) (4), 7 - 12, Japanese
    [Refereed]
    Research institution

  • Zenzo Yamaguchi, Kimihiro Sakagami, Masayuki Morimoto, J. Stuart Bolton, Ichiro Yamagiwa
    2012, Acoustical Science and Technology, 33(1) (1), 56 - 58, English
    [Refereed]
    Scientific journal

  • An experimental study on a cylindrical microperforated panel space sound absorber
    Kimihiro Sakagami, Takayuki Oshitani, Motoki Yairi, Emi Toyoda, Masayuki Morimoto
    A microperforated panel (MPP), which is widely known as one of the most promising alternatives of the next-generation sound absorbers, is typically used with a rigid-back wall with an air-cavity. However, a multiple-leaf MPP space absorber, which does not have any backing structure, double-leaf MPP space absorber (DLMPP) and triple-leaf MPP space absorber (TLMPP) is proposed. However, these are panel-like structure which are limited to where they can be used. In order to develop an MPP space absorber that can be used in more various situations, a trial production of a cylindrical MPP space sound absorber (CMSA) is made with an MPP shaped into a cylindrical. The sound absorption characteristics of a CMSA are measured in a reverberation chamber. As a result, although the absorption coefficient is not very high, a CMSA shows sound absorption characteristics similar to a DLMPP and TLMPP: a resonance peak by a Helmholtz resonator and an additional low frequency absorption by its acoustic permeability appear. The results suggest that a CMSA can be used as a space sound absorber in practical situations. (C) 2012 Institute of Noise Control Engineering.
    INST NOISE CONTROL ENGINEERING, Jan. 2012, NOISE CONTROL ENGINEERING JOURNAL, 60(1) (1), 22 - 28, English
    [Refereed]
    Scientific journal

  • SOUND ABSORPTION CHARACTERISTICS OF A SINGLE MICROPERFORATED PANEL ABSORBER BACKED BY A POROUS ABSORBENT LAYER
    Kimihiro Sakagami, Seiji Kobatake, Ken'ichi Kano, Masayuki Morimoto, Motoki Yairi
    A microperforated panel (MPP) is usually used with an air-back cavity backed by a rigid wall to form a Helmholtz-type resonance absorber. In the case of a common perforated panel with larger perforations, a porous absorbent is usually located behind the panel to add acoustic resistance for efficient sound absorption. In the case of an MPP, if a porous layer is inserted in the cavity, the absorption may be deteriorated by the large acoustic resistance due to the porous absorbent. However, if the resistance is suitably adjusted, it is expected that a porous layer can widen the absorption frequency range by the additional damping by the porous absorbent. In this study, a single-leaf MPP absorber backed by a rigid-back wall with a porous absorbent layer in the cavity is analysed using an electro-acoustical equivalent circuit model and its absorption characteristics are discussed through the numerical examples.
    AUSTRALIAN ACOUSTICAL SOC, Dec. 2011, ACOUSTICS AUSTRALIA, 39(3) (3), 95 - 100, English
    [Refereed]
    Scientific journal

  • Experimental validation of force radiation modes: a novel approach to reduction of sound radiation from vibrating structure
    Yamaguchi Zenzo, Sakagami Kimihiro, Morimoto Masayuki, Bolton J. Stuart
    Sep. 2011, CDROM Proceedings of Inter-Noise 2011 Osaka, English
    International conference proceedings

  • Effect of a honeycomb on the absorption characteristics of double-leaf microperforated panel (MPP) space sound absorbers
    Kimihiro Sakagami, Ippei Yamashita, Motoki Yairi, Masayuki Morimoto
    Sound absorbers using a microperforated panel (MPP) is usually not strong enough for room interior surfaces because MPPs are in general very thin. In order to solve this weakness, the authors proposed to use a honeycomb attached behind an MPP in the air-back cavity. In the authors previous studies a honeycomb is effective to improve the sound absorption performance of an ordinary wall-backed single-leaf MPP sound absorber. The honeycomb can also be applied to a space sound absorbing structures such as a double-leaf MPP space absorber (DLMPP). In this study, the effect of a honeycomb in the air-cavity on the sound absorption characteristics of a DLMPP is theoretically analysed. In the theory a Helmholtz-Kirchhoff integral formulation is utilised. The theory is validated with experimental results. The effect of the honeycomb on the sound absorption characteristics is discussed through the numerical examples calculated by the present theory. The results show that the honeycomb enhances the resonance peak and shifts it to lower freqeuencies. Although the honeycomb is effective to improve the sound absorption performance of a DLMPP at around resonance peak, it does not affect the additional low frequency absorption which is particular to a DLMPP. (C) 2011 Institute of Noise Control Engineering.
    INST NOISE CONTROL ENGINEERING, Jul. 2011, NOISE CONTROL ENGINEERING JOURNAL, 59(4) (4), 363 - 371, English
    [Refereed]
    Scientific journal

  • Effect of a honeycomb on the sound absorption characteristics of panel-type absorbers
    Toyoda Masahiro, Sakagami Kimihiro, Takahashi Daiji, Morimoto Masayuki
    Jul. 2011, Applied Acoustics, Vol. 72, pp. 943-948, English
    [Refereed]
    Scientific journal

  • Zenzo Yamaguchi, J. Stuart Bolton, Kimihiro Sakagami
    The location of a vibration source within a machine is sometimes found to have a significant effect upon its radiated acoustic power. It is known that a simple reduction of vibration cannot always reduce the radiated acoustic power, so that treatments based on analysis of a structure's vibration modes are not always effective. At the same time, radiation mode analysis is known to be a powerful tool for interpreting sound radiation since those modes are independent of a structure's surface vibration. However, knowledge of the radiation modes alone cannot be used directly to understand the relationship between vibration source location and acoustic power radiation. In this paper, it is shown that the radiation mode concept can be extended to understand the relationship between acoustic power and driving force distribution by considering the product of the structure's mobility matrix and the radiation modes: the resulting functions are here defined to be force radiation modes (frad-modes). An example is presented in which the acoustic power radiated by a simply-supported, baffled beam is reduced by using guidance provided by the structure's force radiation modes. The results demonstrate that the force radiation modes can be used to guide the reduction of radiated acoustic power by changing the driving force location without the need to perform additional calculations or experiments. © 2011 Elsevier Ltd. All rights reserved.
    Jun. 2011, Applied Acoustics, 72(7) (7), 420 - 427, English
    [Refereed]
    Scientific journal

  • Excess sound absorption in the normal incidence obtained by two microperforated panel absorbers with different impedance
    Motoki Yairi, Kimihiro Sakagami, Kenichi Takebayashi, Masayuki Morimoto
    A microperforated panel (MPP) absorber is known to be one of the most promising alternatives of the next-generation sound absorbers. However, its absorption frequency range is limited to around two octaves because its absorption solely depends on the Helmholtz resonance mechanism. Therefore, the authors have proposed a combination of two different MPP absorbers in parallel, and revealed its potential for achieving a broader absorption frequency range in terms of excess attenuation. In this study, by the hybrid method of BEM and a mode expansion method, the authors investigate the relationship between the excess attenuation caused by the impedance discontinuity at the boundary of the two different MPPs and the sound absorption coefficient derived using the electro acoustical equivalent circuit model. Measurements of the normal incidence absorption coefficients are carried out to validate the equivalent circuit model, and in the experiments, the configuration of the cavity to realize the parallel arrangements for achieving wideband sound absorption is also discussed referring to the experimental results.
    2011, 40th International Congress and Exposition on Noise Control Engineering 2011, INTER-NOISE 2011, 3, 1966 - 1973, English
    International conference proceedings

  • Sound absorption characteristics of a double-leaf structure composed of a microperforated panel (MPP) and a permeable membrane with a porous layer
    Sakagami Kimihiro, Kobatake Seiji, Morimoto Masayuki
    神戸大学大学院工学研究科, 2011, Memoirs of the Graduate School of Engineering, Kobe University, 第3号,10~15頁, 10 - 15, Japanese
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Tomohito Nakamori, Masayuki Morimoto, Motoki Yairi
    The sound absorption characteristics of a double-leaf space sound absorber consisting of a microperforated panel (MPP) and a permeable membrane (PM) is discussed. A plane sound wave of unit pressure amplitude is supposed to be incident upon the system with the angle of incidence θ. When a PM is on the illuminated side of the system, Z1, acoustic impedance of the MPP, should be replaced with the flow resistance of the PM. The sound absorption and transmission coefficients are averaged over the angle of incidence from 0 to 78 degrees in the half space that gives the sound-field-incidence averaged sound absorption and transmission coefficients, α and τ, respectively. The difference of the absorption and transmission coefficients, α-τ, is employed for the evaluation of the sound absorption performance. The average of the values of α-τ for the incidence from either side corresponds to the diffuse sound absorption coefficient measured in a reverberation chamber.
    2011, Acoustical Science and Technology, 32(1) (1), 47 - 49, English
    [Refereed]
    Scientific journal

  • Motoki Yairi, Kimihiro Sakagami, Kenichi Takebayashi, Masayuki Morimoto
    A micro perforated panel (MPP) absorber is known to be one of the most promising alternatives of the next-generation sound absorbers. However, its absorption frequency range is limited to around two octaves because its absorption solely depends on the Helmholtz resonance mechanism. Therefore, the authors have proposed a combination of two different MPP absorbers in parallel, and revealed its potential for achieving a broader absorption frequency range in terms of excess attenuation. In this study, by the hybrid method of BEM and a mode expansion method, the authors investigate the relationship between the excess attenuation caused by the impedance discontinuity at the boundary of the two different MPPs and the sound absorption coefficient derived using the electro acoustical equivalent circuit model. Measurements of the normal incidence absorption coefficients are carried out to validate the equivalent circuit model, and in the experiments, the configuration of the cavity to realize the parallel arrangements for achieving wideband sound absorption is also discussed referring to the experimental results. © 2011 The Acoustical Society of Japan.
    2011, Acoustical Science and Technology, 32(5) (5), 194 - 200, English
    [Refereed]
    Scientific journal

  • Motoki Yairi, Kimihiro Sakagami, Kenichi Takebayashi, Masayuki Morimoto
    A micro perforated panel (MPP) absorber is known to be one of the most promising alternatives of the next-generation sound absorbers. However, its absorption frequency range is limited to around two octaves because its absorption solely depends on the Helmholtz resonance mechanism. Therefore, the authors have proposed a combination of two different MPP absorbers in parallel, and revealed its potential for achieving a broader absorption frequency range in terms of excess attenuation. In this study, by the hybrid method of BEM and a mode expansion method, the authors investigate the relationship between the excess attenuation caused by the impedance discontinuity at the boundary of the two different MPPs and the sound absorption coefficient derived using the electro acoustical equivalent circuit model. Measurements of the normal incidence absorption coefficients are carried out to validate the equivalent circuit model, and in the experiments, the configuration of the cavity to realize the parallel arrangements for achieving wideband sound absorption is also discussed referring to the experimental results. © 2011 The Acoustical Society of Japan.
    2011, Acoustical Science and Technology, 32(5) (5), 194 - 200, English
    Scientific journal

  • MULTIPLE-LEAF SOUND ABSORBERS WITH MICROPERFORATED PANELS: AN OVERVIEW
    Kimihiro Sakagami, Motoki Yairi, Masayuki Morimoto
    Since the pioneering work by (Maa), multiple-leaf microperforated panel (MPP) sound absorbers of various configurations with different materials have been studied. Multiple-leaf structures are primarily employed to obtain wideband sound absorption. The authors have proposed double-leaf microperforated panel space absorbers (DLMPP), which consist of two MPPs and an air-cavity in-between, without a back wall. A DLMPP is a wideband sound absorber, which is also effective at low frequencies. However, an MPP is still expensive. If one of the MPPs in such a structure can be substituted with another material, such as a permeable membrane, it can be effective and also economical. The authors, therefore, have been exploring various multiple-leaf structures including both MPPs and permeable membranes. This paper gives an overview of our studies on such multiple-leaf sound absorbing structures with MPPs, including a DLMPP, a triple-leaf M PP space absorber, a space sound absorber consisting of an MPP and a permeable membrane. Also it includes a multiple-leaf structure with MPPs and membranes backed by a rigid wall.
    AUSTRALIAN ACOUSTICAL SOC, Aug. 2010, ACOUSTICS AUSTRALIA, 38(2) (2), 76 - 81, English
    [Refereed]
    Scientific journal

  • Reduction of sound radiation by using force radiation modes: Effects of attached mass on force radiation modes
    YAMAGUCHI Zenzo, NAKAHIRA Wataru, SAKAGAMI Kimihiro, MORIMOTO Masayuki, BOLTON Stuart J, YAMAGIWA Ichiro
    Jun. 2010, CD-ROM Proceedings of Inter-Noise 2010, Paper ID: 534, English
    Scientific journal

  • Multiple-leaf sound absorbers with microperforated panels: An overview
    SAKAGAMI Kimihiro, YAIRI Motoki, MORIMOTO Masayuki
    Jun. 2010, CD-ROM Proceedings of Inter-Noise 2010, Paper ID: 89, English
    Scientific journal

  • Kimihiro Sakagami, Kiyotaka Matsutani, Masayuki Morimoto
    So far the electro-acoustical equivalent circuit analysis has been widely used to analyse micro-perforated panel (MPP) absorbers, however, as for the double-leaf MPP the equivalent circuit analysis inevitably includes an approximation. In this paper, the sound absorption characteristics of a double-leaf MPP absorber backed by a rigid wall are analysed by wave theory using Helmholtz-Kirchhoff integral formulation to obtain a strict solution. The present wave theory is experimentally validated with existing measured results. The theory is also compared with the equivalent circuit solutions so that the differences between the two theories appear and the effect of the approximation is clarified. The comparison shows that the difference mainly appears in the vicinity of the resonance peaks: the differences occur in the resonance frequencies and the absorption coefficient at frequencies between the two resonance peaks. (C) 2009 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, May 2010, APPLIED ACOUSTICS, 71(5) (5), 411 - 417, English
    Scientific journal

  • Sound absorption characteristics of a honeycomb-backed microperforated panel absorber: Revised theory and experimental validation
    SAKAGAMI Kimihiro, YAMASHITA Ippei, YAIRI Motoki, MORIMOTO Masayuki
    Apr. 2010, Noise Control Engineering Journal, Vol. 58, No. 2, pp. 157-162, English
    [Refereed]
    Scientific journal

  • 防音扉による低周波音の遮音特性に関する基礎的研究
    SAKAGAMI Kimihiro, KASHITANI Akihiko, MORIMOTO Masayuki, TAKADA Shigetaka
    神戸大学大学院工学研究科, Mar. 2010, 神戸大学大学院工学研究科紀要, 第1号,pp.22-28, 22 - 28, Japanese
    [Refereed]
    Scientific journal

  • Sound absorption characteristics of a microperforated panel absorber backed by an absorbent layer
    SAKAGAMI Kimihiro, KANO Kenichi, MORIMOTO Masayuki, YAIRI Motoki
    神戸大学大学院工学研究科, 2010, MEMOIRS OF THE GRADUATE SCHOOLS OF ENGINEERING AND SYSTEM INFORMATICS, 第2号,pp.14-19, 14 - 19, Japanese
    [Refereed]
    Scientific journal

  • 多孔質吸音材の吸音特性に対する表面保護フィルムの影響
    SAKAGAMI Kimihiro, NISHIO Junko, MORIMOTO Masayuki
    Sep. 2009, 神戸大学都市安全研究センター研究報告, 第13号,pp211-218, Japanese
    Scientific journal

  • Masayuki Morimoto, Kimihiro Sakagami, Noboru Nakajima, Zenzo Yamaguchi, Kazutoshi Michishita
    With the aim to propose a reasonable and effective countermeasure for the elevated structure noise. the sound field radiated by a steel plate girder, which is the main source of the elevated structure noise, have been theoretically analysed. in the present study, steel plate girders are modelled as infinitely long elastic plate strips placed in parallel and numerical examples on the sound field radiated by the steel plate girders are shown. In the analysis of the radiated sound field, the equivalent source method is employed. Effect of the surface absorption on the sound field radiated by the girders is discussed through numerical examples. The results show that the surface absorption is effective for reduction of the radiated sound field, especially in the area that increase of sound pressure due to reflection by adjacent plate girders is observed. Furthermore, to design for reasonable countermeasure, variation of the noise reduction effect due to changing the pattern of surface absorption area on plate girders is classified. (C) 2009 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Sep. 2009, Applied Acoustics, 70(9) (9), 1143 - 1147, English
    [Refereed]
    Scientific journal

  • Effect of a membrane attached to a microperforated panel absorber on its sound absorptiriby; Possibility of adjusting the acoustic properties of a microperforated panel by covering materials
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, NISHIO Junko, YAIRI Motoki
    Sep. 2009, 神戸大学都市安全研究センター研究報告, 第13号,pp.219-226, English
    Scientific journal

  • Kimihiro Sakagami, Masayuki Morimoto, Motoki Yairi
    The sound absorption mechanism of microperforated panel (MPP) absorbers and panel/membrane-type absorbers is both based on a certain resonance system and utilising its resonance effect. However, the relationship between the absorption mechanisms of MPPs and panel/membrane-type absorbers has not been discussed: it is not clarified whether they can occur simultaneously, or how they interfere each other. On the other hand, in a previous study there is an attempt to cause both absorption mechanisms simultaneously. In this paper, using an electro-acoustical equivalent circuit model, their sound absorption mechanisms and their relationship are discussed. In this study, three cases are considered: (1) the case in which only the mass reactance of the MPP is considered, (2) the case in which the losses of the panel is considered, and (3) the case in which the sound absorption of the back wall surface is considered. The results suggest that the microperforated panel absorption, which is Helmhotz-type resonance, and the panel/membrane-type absorption can be regarded as phenomena of the same kind which can be smoothly transformed into each other by changing a parameter, and can be consistently modelled and comprehensively discussed. © 2009 Elsevier Ltd. All rights reserved.
    Aug. 2009, Applied Acoustics, 70(8) (8), 1131 - 1136, English
    [Refereed]
    Scientific journal

  • Wideband sound absorber obtained by combination of two microperforated panel absorbers with different air-cavity depths arranged in parallel
    YAIRI Motoki, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Aug. 2009, CD-ROM Proceedings of Inter-Noise 2009 (Ottawa, Canada), English
    Scientific journal

  • Sound absorption characteristics of a honeycomb-backed microperforated panel absorber: revised theory and experimental validation
    SAKAGAMI Kimihiro, YAIRI Motoki, MORIMOTO Masayuki
    Aug. 2009, CD-ROM Proceedings of Inter-Noise 2010 (Ottawa, Canada), English
    Scientific journal

  • Double-leaf microperforated panel space absorbers: A revised theory and detailed analysis
    SAKAGAMI Kimihiro, NAKAMORI Tomohito, MORIMOTO Masayuki, YAIRI Motoki
    Jan. 2009, Applied Acoustics, Vol.70 , pp.703-709, 703 - 709, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Yoshiki Nagayama, Masayuki Morimoto, Motoki Yairi
    A wider frequency range for sound absorption, a combination of two different microperforated panel (MPP) absorbers with different frequency characteristics, is proposed, and its potential for achieving a broader absorption frequency range is discussed. MPP absorbers are periodically arranged alternately and parallel to each other and the sound absorption characteristics are analyzed by considering the excess attenuation caused by the impedance discontinuity. The average sound absorption coefficient of two MPP absorbers with an air-back cavity and a rigid back wall is calculated. The cavity depth of MPP is varied in the range of 75-200nm and it is found that 50mm and 150mm exhibit the greatest potential for achieving wideband characteristics. It is also found that an MPP absorber with different absorption characteristics but with same cavity depth can be made, with the greatest potential for achieving a wideband absorber at the perforation ratio of 0.15%.
    2009, Acoustical Science and Technology, 30(2) (2), 154 - 156, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Keishi Yoshida, Masayuki Morimoto
    A study was conducted to analyze a double-leaf membrane structure with two permeable leaves (DLPM) theoretically using a Helmholtz-Kirchhoff integral formulation to obtain a general solution. The two permeable membranes were assumed to be of infinite extent with surface densities m1, m2 (kg/m2), flow resistances r1, r2 (Pa s/m), and tensions T1, T2 (N/m). A plane sound wave of unit pressure amplitude pi was assumed to be incident to the first permeable membrane (PM1)at the angle of incidence θ. The surface pressure of the illuminated side of PM1 was expressed by an equation using a Helmholtz-Kirchhoff integral. It was demonstrated that it was necessary to evaluate the energy dissipated in the structure to evaluate the sound absorption performance.
    2009, Acoustical Science and Technology, 30(5) (5), 390 - 392, English
    [Refereed]
    Scientific journal

  • Effect of an elastic support on the sound absorption characteristics of microperforated panel absorbers
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    Sep. 2008, 神戸大学都市安全研究センター研究報告, 12, English
    Scientific journal

  • Application of microperforated panel absorbers to room interior surfaces
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    Sep. 2008, International Journal of Acoustics and Vibration, 13 (3) 120-124, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Masayuki Morimoto, Motoki Yairi, Atsuo Minemura
    Microperforated panel (MPP) absorbers are promising as a basis for the next-generation of sound absorbing materials. MPPs are typically made of a thin metal or plastic panel. However, thin limp panels are generally not suitable as an interior finish of room walls because they do not have sufficient strength, which prevents practical application of MPPs as an interior finish of room walls. In order to overcome the lack of appropriate strength required for room walls, it is possible to make an NIPP out of a thick panel. However, thick MPPs are usually not efficient because the resistance and/or reactance become too high. In this study, trial production of thick MPPs and measurement of their normal absorption coefficients were carried out. Results show that efficient absorption can be given with a thick NIPP by using a tapered perforation. (C) 2006 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Feb. 2008, APPLIED ACOUSTICS, 69(2) (2), 179 - 182, English
    [Refereed]
    Scientific journal

  • Double-leaf microperforated panel space absorbers: A revised theory and detailed analysis
    Sakagami, Kimihiro, Nakamori, Tomohito, Morimoto, Masayuki, Yairi, Motoki
    Sep. 2007, CD-ROM Proceedings of 19th International Congress on Acoustics, CD-ROM (invited paper), English
    Scientific journal

  • Double-leaf microperforated panel space absorbers: An experimental study for further improvement
    Yairi, Motoki, Sakagami, Kimihiro, Morimoto, Masayuki
    Sep. 2007, CD-ROM Proceedings of 19th International Congress on Acoustics, CD-ROM (invited paper), English
    International conference proceedings

  • Recent developments in applications of microperforated panel absorbers
    Sakagami, Kimihiro, Morimoto, Masayuki, Motoki, Yairi
    Jul. 2007, CD-ROM Proceedings of 14th International Congress on Sound and Vibration, CD-ROM (Keynote paper), English
    Scientific journal

  • A basic study on the analysis of the sound field around an axial symmetric obstacle by boundary expansion method
    Tanigawa, Masaki, Fukuwaka, Naoko, Matsuura, Yukiko, Sakagami, Kimihiro, Morimoto, Masayuki
    神戸大学, Mar. 2007, Memoirs of Graduate School of Science and Technology Kobe University (B), 25-B, 21-29, 21 - 29, Japanese
    [Refereed]
    Scientific journal

  • Sound absorption characteristics of a panel absorber with an air-back cavity of non-uniform depth
    Sakagami, Kimihiro, Morimoto, Masayuki
    Kobe University, Mar. 2007, Memoirs of Graduate School of Science and Technology Kobe University, 25-A, 25-31, 25 - 31, English
    [Refereed]
    Scientific journal

  • Yukiko Matsuura, Masayuki Morimoto, Kimihiro Sakagami, Masaki Tanigawa
    This study deals with the development of the approximate method to analyze the sound field around equally spaced finite obstacles, using the periodic boundary condition. First, on the assumption that the equally spaced finite obstacles are the periodically arranged obstacles, the sound field is analyzed by boundary integral equation method with a Green's function which satisfies the periodic boundary condition. Furthermore, by comparing these results and the exact solution by using the fundamental solution as Green's function, the validity of the approximate method is also investigated. Next, in order to evaluate the applicability of the approximate method, the simple formula using some parameters, i.e., the frequency, the period, and the number of obstacles, etc., is proposed. The results of the sound field analysis applied the formula are presented. (c) 2006 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Oct. 2006, Applied Acoustics, 67(10) (10), 982 - 995, English
    [Refereed]
    Scientific journal

  • K Sakagami, M Morimoto, W Koike
    Microperforated panel (MPP) absorbers are promising as a basis for the next-generation of sound absorbing materials. Typically, they are backed by an air-cavity in front of a rigid wall such as a ceiling or another interior surface of a room. Indeed, to be effective, MPP absorbers require the Helmholtz-type resonance formed with the backing cavity. Towards the creation of an efficient sound-absorbing structure with MPPs alone, the acoustical properties of a structure composed of two parallel MPPs with an air-cavity between them and no rigid backing is studied numerically. In this double-leaf MPP (DLMPP) structure, the rear leaf (i.e., the MPP remote from the incident sound) plays the role of the backing wall in the conventional setting and causes resonance-type absorption. Moreover, since a DLMPP can work efficiently as an absorber for sound incidence from both sides, it can be used efficiently as a space absorber, e.g., as a suspended absorber or as a sound absorbing panel. The sound absorption characteristics of the double-leaf MPP are analysed theoretically for a normally incident plane wave. The effects of various control parameters are discussed through a numerical parametric study. The absorption mechanisms and a possible design principle are discussed also. It is predicted that: (1) that a resonance absorption, similar to that in conventional type MPP absorbers, appears at medium-to-high frequencies and (2) that considerable "additional" absorption can be obtained at low frequencies. This low-frequency absorption is similar to that of a double-leaf permeable membrane and can be an advantage compared with the conventional type of MPP arrangement. (c) 2005 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Jul. 2006, APPLIED ACOUSTICS, 67(7) (7), 609 - 619, English
    [Refereed]
    Scientific journal

  • Application of microperforated panels to room interior surfaces: An overview
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki, MINEMURA Atsuo
    Jun. 2006, CD-ROM Proceedings of WESPAC IX, Seoul, Korea, pp. 1-6, English
    International conference proceedings

  • K Sakagami, T Uyama, M Morimoto, M Kiyama
    This paper presents a method to predict the reverberation absorption coefficient of a finite-size membrane absorbers composed of a single- or double-leaf membrane structure of various configurations. In order to predict the sound absorptivity of such an absorber, it is needed to consider that sound is incident from both sides of the absorber, which has not been accounted for the previous studies on membrane absorbers. The edge effect also needs to be considered if the absorber is rather small. The present method is established based on the theory for absorbers hanged in a reverberation chamber developed by Fujiwara and Makita [J Acoust Soc Jpn (E) 1980; 1:37-45]. The same theory requires the fraction of energy dissipation in the absorber, which can be obtained by the difference of absorption and transmission coefficients, and the difference is calculated by the theories for various membrane structures presented in the authors' previous work. An experimental study was also conducted to validate the present method: the predicted values showed good agreement with the measured ones. The numerical examples calculated by the present method are also presented to discuss the effect of the various control parameters, and it is suggested how to improve the sound absorption performance of double-leaf membrane absorbers with a permeable and an impermeable leaves. (C) 2004 Elsevier Ltd. All rights reserved.
    ELSEVIER SCI LTD, Jun. 2005, APPLIED ACOUSTICS, 66(6) (6), 653 - 668, English
    [Refereed]
    Scientific journal

  • KONNO Yoshisato, SAKAGAMI Kimihiro, YAMAMOTO Minoru, YAMAMOTO Kohei
    Bridges are mainly made of two types plate component, slab and girder. Such components are vibrated by road traffic, and radiate structure borne sound. In this paper calculation methods for the structure borne sound are derived by the theory of thin plate vibration. Test-run of heavy trucks on different type bridges and vibration force measurement with hammer impact on bridge surface are carried out. From those tests the vibration force caused by traffic is estimated. With the aid of the vibration force and the calculation formulas, the radiated sound is calculated. Also we compared the calculated results with measured sound and could explain the sound field with this method. It is shown that a good agreement is obtained between the theoretically predicted value and the measured one.
    Japan Society of Civil Engineers, Apr. 2005, Journals of the Japan Society of Civil Engineers, 787/I-71, 105-115(787) (787), 105 - 115, Japanese
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Masayuki Morimoto, Motoki Yairi
    The effect of vibration of a microperforated panel (MPP) absorber on its sound absorption characteristics was investigated. The effect of the MPP mass appeared at the resonance peak only, both the peak value and frequency change with the mass. If the MPP is light-weight and set into vibration, the flow resistance was lowered due to its sound-induced vibration. The results show that light-weight double-leaf MPP (DLMPP) exhibits significant drop in absorptivity at low frequencies.
    Mar. 2005, Acoustical Science and Technology, 26(2) (2), 204 - 207, English
    [Refereed]
    International conference proceedings

  • Acoustical properties of microperforated panel absorbers with various configurations of the back cavity
    Motoki Yairi, Kimihiro Sakagami, Masayuki Morimoto, Atsuo Minemura
    A series of experiments was performed on a microperforated panel absorber (MPA) with various back cavity configurations, namely, a thin impermeable sheet, a thin permeable sheet, and a paper honeycomb panel, and the effect of these configurations on the absorption coefficient of the MPA was discussed. The experiment results for the reverberation sound absorption coefficient suggest that the absorption characteristics of the MPA can be improved by using a paper honeycomb panel. The mechanism for increasing the sound absorption by using a paper honeycomb panel is also discussed with reference to measurements taken of the normal incidence absorption coefficient. The results also show that the characteristics of an MPA can be improved by modifying the design of the MPA itself as well as by using an appropriate backing structure configuration.
    2005, 12th International Congress on Sound and Vibration 2005, ICSV 2005, 1, 339 - 346, English
    International conference proceedings

  • Sakamoto Shinichi, Sakagami Kimihiro, Hanyu Toshiki
    Acoustical Society of Japan, 2005, Acoustical science and technology, 26(2) (2), 89 - 89, English

  • Theoretical analysis of an acoustic gain by a stage riser with perildic ribs
    NAKANISHI Shinsuke, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 2004, CD-ROM Proceedings of The 18th International Symposium on Room Acoustics;Design&Science 2004(RADS2004),Awaji,Japan, 27, 525 - 528, English
    [Refereed]
    International conference proceedings

  • Effect of constructions on an acoustic gain by a stage riser
    NAKANISHI Shinsuke, MORIMOTO Masayuki, SAKAGAMI Kimihiro
    2004, CD-ROM Proceedings of The 18th International Congress on Acoustics,Kyoto,Japan, We2.B2.3, English
    [Refereed]
    International conference proceedings

  • Effect of a mecroperforated panel inside the cavity on structure-borne sound radiation from a double-leaf structure(invited paper)
    YAIRI Motok, SAKAGAMI Kimihiro, MORIMOTO Masayuki, MINEMURA Atsuo, ANDOW Kei
    2004, CD-ROM Proceedings of The 18th International Congress on Acoustics,Kyoto,Japan, Tu5.B2.1, English
    [Refereed]
    International conference proceedings

  • Detailed analysis of the effect of vibration of a microperforated panel on its sound absorption characteristics
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    2004, CD-ROM Proceedings of The 18th International Symposium on Room Acoustics;Design&Science 2004(RADS2004),Awaji,Japan, English
    [Refereed]
    International conference proceedings

  • A basic study on double-leaf microperfonated panel absorbers
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, KOIKE Wakana
    2004, CD-ROM Proceedings of The 18th International Congress on Acoustics,Kyoto,Japan, We.P2.16, English
    [Refereed]
    International conference proceedings

  • Motoki Yairi, Kimihiro Sakagami, Masayuki Morimoto, Atsuo Minemura, Kei Andow
    Structure-borne sound radiation from a double-leaf structure with a porous absorptive layer in the cavity is studied theoretically as well as experimentally. The study is for establishing a countermeasure to reduce the structure-borne noise radiated from an interior leaf into rooms and for clarifying its reduction effect. The sound field radiated from a double-leaf elastic plate with layers of arbitrary media in the cavity set into vibration by a point force excitation is theoretically analyzed. The effect of the bulk vibration of an absorptive layer is also considered by a simple model into the present theory. Radiation reduction of an inner-layer derived from the theory is experimentally validated. Parametric studies reveal that increasing the ratio of an absorptive layer thickness to the cavity depth is effective to reduce the structure-borne sound radiation but high flow resistivity of the absorbent material is not necessarily required. A practical equation to predict the mass-air-mass resonance frequency for absorbent cavity case is given in a simple form. © 2002 Elsevier Science Ltd. All rights reserved.
    Apr. 2003, Applied Acoustics, 64(4) (4), 365 - 384, English
    [Refereed]
    Scientific journal

  • Effects of acoustical damping with a microperforated panel to reduce the structure-borne sound radiation from a double-leaf structure.
    YAIRI Motoki, SAKAGAMI Kimihiro, MORIMOTO Masayuki, MINEMURA Atsuo, ANDOW Kei
    2003, CD-ROM Proceedings of International Conference on Sound and Vibration(ICSV10), 未記入, English
    Scientific journal

  • Sound field radiated by infinitely long elastic plate strips placed in parallel.
    MICHISHITA K, YAMAGUCHI Z, NAKAJIMA N, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Kobe University, 2003, Memoirs of the faculty of engineering, Kobe University., 50,27-36, 27 - 35, English
    Scientific journal

  • Membranes and membrane structures for acoustical applications: an overview.
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, KIYAMA Masakazu
    2003, CD-ROM Proceedings of The Eighth Western Pacific Acoustics Conference, MC44, English
    International conference proceedings

  • Masayuki Morimoto, Masakazu Kiyama, Kimihiro Sakagami
    Double-leaf membranes with a permeable leaf on the sound incidence side are usually used as roofs in actual membrane-structure buildings. They are modelled as of infinite extent, and their acoustic properties are theoretically analysed. The theory is experimentally validated. The permeability can significantly improve the sound absorption performance at high frequencies, and makes the characteristics similar to those of cavity-backed porous absorbents. At low frequencies the permeability also affects the sound absorption and insulation performance. At middle frequencies, the characteristics changed according to the permeability: a mass-spring peak appears if it is very high, and vanishes if lower. These effects are strongly dependent upon the mass of leaves, flow resistivity, cavity depth, etc. A detailed discussion is also given to shed some light on the mechanism of these effects. (C) 2002 Elsevier Science Ltd. All rights reserved.
    ELSEVIER SCI LTD, Aug. 2002, Applied Acoustics, 63(8) (8), 911 - 926, English
    [Refereed]
    Scientific journal

  • Kei Andow, Atsuo Minemura, Masayuki Morimoto, Eiji Sakagami, Kimihiro Sakagami, Motoki Yairi
    The sound radiation from a double-leaf elastic plate subjected to a point force excitation is investigated theoretically, to gain a fundamental insight into the sound radiation from an interior panel of a double-leaf structure in buildings. The effects of the interior panel on the sound radiation, which show a negative effect at low frequencies due to the mass-air-mass resonance, are discussed in detail. The theory is validated experimentally. As a measure of the efficiency of the interior leaf in reducing noise radiation, the radiation reduction is defined in this study, and it is found useful for predicting the sound radiation due to the structure-borne sound in building elements. Parametric studies through theoretical results are made to clarify the effects of the parameters of the sound radiation system, and to gain a fundamental insight into the control of structure-borne noise radiation. It is shown that it is difficult to reduce the radiated sound power by an interior panel alone, even if its mass is increased. (C) 2002 Elsevier Science Ltd. All rights reserved.
    ELSEVIER SCI LTD, Jul. 2002, Applied Acoustics, 63(7) (7), 737 - 757, English
    [Refereed]
    Scientific journal

  • On the dissipation of acoustic energy in a thin, infinite, poroelastic plate
    KV Horoshenkov, K Sakagami, M Morimoto
    The Helmholtz integral equation formulation is used to produce an exact solution for the sound field reflected from an infinite, thin, porous, elastic plate. The acoustic properties of the porous material of the plate are predicted using an effective fluid assumption. The effect of an air cavity behind the plate is considered. A parametric study is performed to predict the effect on the acoustic properties of variations of the physical parameters of the poroelastic plate. It is shown that thin, light, poroelastic plates can provide high values of the acoustic absorption even for low frequency sound. This effect can be exploited to design compact noise control systems with improved acoustic performance.
    S HIRZEL VERLAG, Jul. 2002, ACTA ACUSTICA UNITED WITH ACUSTICA, 88(4) (4), 500 - 506, English
    [Refereed]
    Scientific journal

  • Zihou Meng, Kimihiro Sakagami, Masayuki Morimoto, Guoan Bi, Kot Chichung Alex
    An analytic method is used to extend the sound impulse response of a room. It is based on the extrapolation theory for band-limited signals. Only two matrix operations are needed for extending a discrete impulse response. Due to the approximation of the geometrical acoustic model of the observed data and the computation errors, the problem may be ill-conditioned. The optimum regularization method is used to solve the ill-posed problem, For discrete signals, the extrapolation is not unique, therefore additional constraints are used to obtain the admissible result. The method is evaluated with a set of psychoacoustic experiments. The evaluations are made on five psychological characteristics, and a general conclusion is given based on general fuzzy clustering.
    Mar. 2002, IEEE Transactions on Speech and Audio Processing, 10(3) (3), 167 - 172, English
    [Refereed]
    Scientific journal

  • Mizutani Koichi, Sakagami Kimihiro
    Acoustical Society of Japan, 2002, Acoustical science and technology, 23(1) (1), 28 - 28, English

  • The role of reflections from behind the listener in spatial impression
    M Morimoto, K Iida, K Sakagami
    This paper describes the results of two subjective experiments to clarify the role of reflections arriving from behind the listener in the perception of spatial impression. The experiments investigate the effects of reflections from behind the listener on both listener envelopment (LEV) and auditory source width (ASW) and which is more effective for LEV, the early or late reflections. The results of experiments clearly show that: (1) The listener can perceive LEV and ASW as two distinct senses of a sound image. (2) The role of reflections arriving from behind the listener is to increase LEV in spatial impression. Namely LEV increases as the relative reflection energy of sound arriving from behind the listener increases. (3) The early reflections also contributes to the perception of LEV, while (4) the late reflections are more effective for LEV than the early ones. However, it cannot be definitely concluded whether C-80 affects LEV or not. (C) 2000 Elsevier Science Ltd. All rights reserved.
    ELSEVIER SCI LTD, Feb. 2001, APPLIED ACOUSTICS, 62(2) (2), 109 - 124, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Toru Uyama, Masayuki Morimoto, Masakazu Kiyama
    2000, Journal of the Acoustical Society of Japan (E) (English translation of Nippon Onkyo Gakkaishi), 21(2) (2), 107 - 109, English
    [Refereed]
    Scientific journal

  • Kazutoshi Michishita, Kimihiro Sakagami, Masayuki Morimoto, U.Peter Svensson
    The noise which is caused by vibration of steel plate girders of a motorway is studied. This type of noise is often referred to as elevated structure noise, and has its main component within the frequency range 500 Hz-1 kHz. Since a steel plate girder can be considered as a rectangular plate with an extreme aspect ratio, the sound field radiated by a baffled elastic plate strip of infinite length, which is the simplest model of a steel plate girder, was theoretically analyzed in the preceding paper. However, a real motorway construction is more appropriately modelled by an unbaffled strip. Thus the unbaffled condition has been analyzed numerically in this paper. The method of equivalent sources is used. The main features of the radiated sound field are discussed in the light of numerical examples, and compared with those of a baffled strip. Two vibration patterns, i.e. an idealized piston vibration and flexural vibration excited by a moment are considered. Furthermore, in order to determine the far-field range of an infinitely long plate, the variation of the radiated sound field with the distance is discussed.
    Elsevier Science Ltd, 2000, Applied Acoustics, 61(1) (1), 45 - 63, English
    [Refereed]
    Scientific journal

  • Kazutoshi Michishita, Zenzo Yamaguchi, Kimihiro Sakagami, Masayuki Morimoto
    For understanding the phenomenon nature of the elevated structure noise around motorways, theoretical studies concerning the main source are needed. Steel plate girders of elevated motorways are the main source of the elevated structure noise. Considering the real conditions, it is necessary to clarify the effect of a concrete slab on the radiated sound field from a steel plate girder. In the present study, a steel plate girder in contact with a concrete slab is modelled by an infinitely long elastic plate strip in contact with a vertical reflecting surface. The method of equivalent sources is used. The sound field radiated by the elastic plate strip is illustrated by numerical examples. The main effects of a slab on the sound field are discussed. Furthermore, the variation of the effects due to the varying height of a plate girder is demonstrated. It is shown that a concrete slab does not affect significantly the sound field radiated by a plate girder in the range of 500-1000 Hz at most receiving points, which is the frequency range of the main interest in the study on the elevated structure noise. © 2000 Elsevier Science Ltd. All rights reserved.
    Elsevier Ltd, 2000, Applied Acoustics, 61(4) (4), 413 - 425, English
    [Refereed]
    Scientific journal

  • M. Morimoto, M. Daido, K. Sakagami, S. Nakanishi
    This paper analyzes the effect of an excitation force from a string instrument on the acoustic properties of a stage floor. The theory [9] Nakanishi S, Sakagami K, Daido M, Morimoto M. Effect of an air-back cavity on the reflected sound held of a spherical sound wave by an infinite elastic prate driven to vibration by a point force. Applied Acoustics, in press., for a spherical wave reflected by an air-cavity backed elastic plate driven into vibration by a point force, is modified. A measurement of an excitation force, exerted from a violoncello into a wooden riser, is performed. The numerical examples with the measured force demonstrate that the effect under consideration is significant at some frequencies. The modified theory explains the phenomenon called resonant support which is caused by the sound wave reflected by a rigid floor and the sound wave radiated from the riser top. (C) 1998 Elsevier Science Ltd. All rights reserved.
    ELSEVIER SCI LTD, May 1999, Applied Acoustics, 57(1) (1), 17 - 27, English
    [Refereed]
    Scientific journal

  • M Morimoto, M Daido, K Sakagami, S Nakanishi
    The effect of an air-back cavity on the spherical wave reflected by the stage floor is analyzed theoretically. An air-cavity backed infinite elastic plate is driven to vibration by a point force. A closed form expression for the far-field solution is derived by coupling the Helmholtz integrals for sound field and the equation of the plate motion. Numerical examples demonstrate four main features of the sound field. Two of them are absent for the plate without the air-cavity: one is a panel absorption dip owing to the plate and air-cavity resonance system. The other is small peaks and dips due to the acoustic resonances of the air-cavity. (C) 1998 Elsevier Science Ltd. All rights reserved.
    ELSEVIER SCI LTD, Apr. 1999, Applied Acoustics, 56(4) (4), 241 - 256, English
    [Refereed]
    Scientific journal

  • D. Takahashi, M. Morimoto, M. Daido, S. Nakanishi, K. Sakagami
    This paper theoretically analyses the reflected sound field by an infinite elastic plate which generates its own sound field due to a point for ce excitation. The plate is a theoretical model for the stage floor. A closed form expression for the far-field solution was derived by coupling the Helmholtz equation for sound fields surrounding the plate and the equation of motion for the plate. The solution indicates that the field above the plate excited by a point force consists of the reflected sound by the plate at rest without the point force and the radiated sound from the plate excited bl? the point force. The general features of the field reflected by the vibrating plate with the point force excitation are discussed with the theoretical solution and numerical examples. The numerical examples are also presented to demonstrate the effects of the plate parameters on the sound field. (C) 1998 Elsevier Science Ltd. All rights reserved.
    ELSEVIER SCI LTD, Dec. 1998, Applied Acoustics, 55(4) (4), 253 - 273, English
    [Refereed]
    Scientific journal

  • A basic study on acoustic properties of double-leaf membranes
    M Kiyama, K Sakagami, M Tanigawa, M Morimoto
    Low absorptivity is a problem associated with many membrane-structure buildings and can result in a long reverberation time which degrades the acoustic environment. One possible solution to this problem may be the use of membranes to form the ceiling. The present study examines the acoustic properties of double-leaf membranes, which have recently become widely used in the construction of membrane-structure buildings. Parametric studies with theoretically calculated results show the effects of various parameters on absorptivity and transmissibility. Experimental results confirm the theory. The possibility of using double-leaf membranes to construct the absorption structures is then discussed. (C) 1998 Elsevier Science Ltd. All right reserved.
    ELSEVIER SCI LTD, Jul. 1998, APPLIED ACOUSTICS, 54(3) (3), 239 - 254, English
    [Refereed]
    Scientific journal

  • Daiji Takahashi, Masayuki Morimoto, Masakazu Kiyama, Kimihiro Sakagami
    A detailed analysis is carried out to clarify the mechanisms governing the acoustic performance of a permeable membrane and the effects of various material parameters. For this purpose, the theoretical solutions for the reflected and transmitted sound fields by an infinite permeable membrane which have been derived in a previous paper(1) are approximated to obtain simple expressions for normal incidence absorption and transmission coefficients. An electrical circuit analogy is employed for a detailed analysis in which the particle velocity is separated into two components, i.e. the mass and the permeability, which is helpful in understanding their contributions to the acoustic properties of the permeable membrane. These considerations are aimed at demonstrating the effects of the parameters on the acoustic properties as well as explaining the following particular phenomena which are observed in the acoustic properties of a permeable membrane: the decrease of the sound energy absorbed in the structure al low frequencies and the increase of transmission loss at low frequencies due to the permeability. The optimal value of flow resistance for the most effective absorption is also obtained from those solutions. (C) 1998 Elsevier Science Ltd. All rights reserved.
    ELSEVIER SCI LTD, Jun. 1998, Applied Acoustics, 54(2) (2), 93 - 111, English
    [Refereed]
    Scientific journal

  • Reflection of a Spherical Sound Wave by an Infinite Elastic Plate with an Air-Back Cavity
    K. Sakagami, S. Nakanishi, M. Daido, M. Morimoto, D. Takahashi
    In this paper, the reflection of a spherical sound wave by an infinite elastic plate with an air-back cavity is theoretically investigated. A far-field expression in closed form for the reflected sound field which includes the effects of the plate vibration excited by the surrounding sound field is derived analytically. The energy ratio of the reflected sound wave by an infinite elastic plate to that by an infinite rigid immovable plate is defined. The ratio is found to take the same form as the energy reflection coefficient of an air-cavity backed infinite elastic plate which the authors have previously derived in the case of a plane wave incidence. This is to say that the effects of the parameters relating to the sound reflecting system should appear in the same manner as in the case of plane wave incidence. The effects of the cavity on the sound reflectivity, which is a dip due to the resonance of mass-spring system consisting of the plate and the cavity and dips due to the acoustic resonance of the cavity, are discussed in detail.
    Nov. 1997, Acustica, 83(6) (6), 963 - 971, English
    Scientific journal

  • Sound absorption of a cavity-backed membrane: A step towards design method for membrane-type absorbers
    K Sakagami, M Kiyama, M Morimoto, D Takahashi
    This paper deals with a theoretical study of the sound absorption characteristics of a membrane-type sound absorber. A closed-form analytical solution for the sound absorption coefficient of an infinite membrane with an air-back cavity is produced by making a minor modification to the solution for a cavity-backed infinite elastic plate which was derived in the previous paper. To analyse the mechanism of absorption, the solution is rearranged in a form which points out the contribution of each element of a membrane-type sound absorber. The contribution of the cavity is found to be dominant, and that of the absorptivity of the source side surface of the membrane is rather small. In the case of an elastic plate, the contribution of the loss factor is found negligible. The effects of the parameters of the sound absorption system are discussed in the light of calculated results. Furthermore, the method to predict the peak-frequency and the peak value of the oblique-incident absorption coefficient of the membrane-type sound absorber is presented. The method satisfactorily explains the relationship between the absorption characteristics and the parameters. It is also applicable to panel absorbers. It can be useful for the design of the purpose-made membrane-type or panel absorbers, and for the sound field prediction within boundaries made from this type of absorber. Copyright (C) 1996 Elsevier Science Ltd.
    ELSEVIER SCI LTD, Nov. 1996, APPLIED ACOUSTICS, 49(3) (3), 237 - 247, English
    [Refereed]
    Scientific journal

  • Acoustic properties of permeable membranes
    D Takahashi, K Sakagami, M Morimoto
    Membranes used for building materials have a certain degree of acoustic permeability, which has been disregarded in general membrane-vibration theory, and may cause serious effects especially on the acoustic properties. In this study, a theory for sound absorption of, and sound transmission through, a single permeable membrane is developed. Subsequently, sound absorption of structures composed of air layers, absorptive layers, and the facings of permeable membranes is investigated theoretically, and discussed in comparison with the experimental data measured by using the reverberation-room method. The results are in fairly good agreement; thus the present theory should give an effective tool for prediction of the acoustic properties of this type of membrane structure. (C) 1996 Acoustical Society of America.
    AMER INST PHYSICS, May 1996, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, 99(5) (5), 3003 - 3009, English
    [Refereed]
    Scientific journal

  • Acoustic properties of an infinite elastic plate backed by multiple layers
    K Sakagami, H Gen, M Morimoto, D Takahashi
    In this paper the reflected sound field from an infinite elastic plate backed by multiple layers is analyzed theoretically to clarify the effects of a multiple layer backing on the acoustic properties of the elastic plate. In order to apply the theory to almost all practical cases, the cavity is modelled with three layers of arbitrary media in the analysis. A closed form expression of the strict solution for the reflected sound field is derived. The theory also can be applied to predict the sound absorptivity of panel absorbers. The theoretical results are compared with existing measured data to verify the accuracy of the theory. The theoretical predictions are in fairly good agreement with the measured results. Furthermore, the effects of the change in position, thickness and flow resistivity of the absorptive layer in a cavity on the absorptivity of panel absorbers are discussed with theoretical results. A few examples of the calculated oblique incident reflection coefficient, which is the most fundamental and important to consider the effects of early reflections, are shown and discussed. By the effects of the absorptive layer, the low frequency component is reduced more significantly than is seen in the case of air back cavity.
    S HIRZEL VERLAG, Jan. 1996, ACUSTICA, 82(1) (1), 45 - 53, English
    [Refereed]
    Scientific journal

  • Effect of permeability on acoustic properties of double-leaf membranes
    M Kiyama, K Sakagami, M Morimoto
    INST ACOUSTICS, 1996, INTER-NOISE 96 - THE 1996 INTERNATIONAL CONGRESS ON NOISE CONTROL ENGINEERING, 25TH ANNIVERSARY CONGRESS - LIVERPOOL, PROCEEDINGS, BOOKS 1-6, 955 - 958, English
    [Refereed]
    International conference proceedings

  • A basic study on acoustic properties of double-leaf membranes
    K Sakagami, M Kiyama, M Tanigawa, M Morimoto
    INST ACOUSTICS, 1996, INTER-NOISE 96 - THE 1996 INTERNATIONAL CONGRESS ON NOISE CONTROL ENGINEERING, 25TH ANNIVERSARY CONGRESS - LIVERPOOL, PROCEEDINGS, BOOKS 1-6, 931 - 934, English
    [Refereed]
    International conference proceedings

  • Sound absorption of layered structures with permeable membranes
    D TAKAHASHI, K SAKAGAMI, M MORIMOTO
    SINTEF, 1995, ICA 95 - PROCEEDINGS OF THE 15TH INTERNATIONAL CONGRESS ON ACOUSTICS, VOL II, 2, 673 - 676, English
    International conference proceedings

  • Kimihiro Sakagami, Masayuki Morimoto, Daiji Takahashi
    In this paper, the reflection of a spherical sound wave by an infinite elastic plate is theoretically investigated. A far-field expression of the reflected field including the effects of the plate's elastic vibration is analytically derived in an explicit closed form. The energy ratio of the reflected sound wave by an infinite elastic plate to that by an infinite rigid plate is defined. It is shown that the ratio takes the same form as the energy reflection coefficient of an infinite elastic plate which has been derived for plane wave incidence by the authors. Thus, it is found that the effects of the plate's properties and the specific acoustic admittance of the plate surface appear in the same manner as seen in the case of plane wave incidence. Some numerical examples are shown, and the main features of the reflected sound field are discussed. © 1995, Acoustical Society of Japan. All rights reserved.
    1995, Journal of the Acoustical Society of Japan (E) (English translation of Nippon Onkyo Gakkaishi), 16(2) (2), 71 - 76, English
    [Refereed]
    Scientific journal

  • Kimihiro Sakagami, Masayuki Morimoto, Daiji Takahashi
    As changes in timbre of reflected sounds due to the difference of material of the boundaries are experienced, the elastic vibration of the boundaries may affect the reflected field. Thus it is required to take into account the effects of the elastic vibration of the boundaries. In this paper, the reflected sound field from an elastic plate with infinite extent is analyzed theoretically. The effects of properties of the plate and the angle of incidence of sound wave on the reflection characteristic of an elastic plate are discussed. © 1993, Acoustical Society of Japan. All rights reserved.
    1993, Journal of the Acoustical Society of Japan (E) (English translation of Nippon Onkyo Gakkaishi), 14(2) (2), 85 - 90, English
    [Refereed]
    Scientific journal

■ MISC
  • A basic study on the application of plenum structure to a door
    SAKAGAMI Kimihiro
    Lead, Jun. 2022, 音響技術, (198) (198), 76 - 79, Japanese
    [Invited]
    Introduction scientific journal

  • Acoustic environment in a residential area during the state of emergency (April-May 2020)
    Kimihiro Sakagami
    Lead, Dec. 2021, 騒音制御, 45(6) (6), 259 - 262, Japanese
    [Invited]
    Introduction scientific journal

  • プレナム構造のドアへの適用に関する簡易実験
    阪上公博, 奥園健
    Lead, Mar. 2020, 神戸大学大学院工学研究科・システム情報学研究科紀要, (12) (12), Japanese
    [Invited]
    Introduction research institution

  • グラフィクスリテラシー教育研究センター設立の趣旨
    鈴木広隆, 阪上公博
    Last, Mar. 2020, 神戸大学大学院工学研究科・システム情報学研究科紀要, (12) (12), Japanese
    [Invited]
    Introduction research institution

  • Social Distanceを保つための公開コンペ「はなれてつなぐ」について
    鈴木広隆, 多賀謙蔵, 阪上公博
    Last, Mar. 2020, 神戸大学大学院工学研究科・システム情報学研究科紀要, (12) (12), Japanese
    [Invited]
    Introduction research institution

  • Some examples of usage of microperforated panel absorbers
    SAKAGAMI Kimihiro
    Dec. 2019, Architectural acoustics and noise control, (188) (188), 1 - 7, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • Acoustical materials and backing structure
    SAKAGAMI KIMIHIRO
    Acoustical Society of Japan, Aug. 2018, Journal of the Acoustical Society of Japan, 74(8) (8), 448 - 455, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • Implementation experiment of a honeycomb-backed MPP sound absorbing system in a meeting room
    SAKAGAMI KIMIHIRO, 矢入 幹記, 奥園 健, 羽入 敏樹, 星 和磨, 原田 慎史, 高橋 誠治, 上田 泰孝
    日本音響材料協会, Jun. 2017, Architectural acoustics and noise control, 46(178) (178), 58 - 62, Japanese
    [Refereed]
    Report scientific journal

  • Resonator type sound absorbing system
    SAKAGAMI Kimihiro
    共鳴器型吸音機構について,筆者の最新の研究成果も交えて総説した.
    日本音響材料協会, Mar. 2017, Architectural acoustics and noise control, 46(177) (177), 15 - 20, Japanese
    [Invited]
    Introduction scientific journal

  • Tips for the application of smartphones to acoustics measurements
    SAKAGAMI KIMIHIRO, SATOH FUMIAKI, OMOTO AKIRA
    日本音響材料協会, Mar. 2016, Architectural acoustics and noise control, 45(173) (173), 44 - 47, Japanese
    [Invited]
    Introduction scientific journal

  • Space sound absorbers with a microperforated panel (MPP)
    阪上 公博, 矢入 幹記, 豊田 政弘
    日本騒音制御工学会, Sep. 2015, 公益社団法人日本騒音制御工学会秋季研究発表会講演論文集 = Proceedings of the autumn meeting, the Institute of Noise Control Engineering of Japan, 115 - 118, Japanese

  • Applications of the next-generation sound absorbing materials : Microperforated panels (MPP) and permeable membranes
    阪上 公博, 矢入 幹記
    日本騒音制御工学会, Sep. 2014, 公益社団法人日本騒音制御工学会秋季研究発表会講演論文集 = Proceedings of the autumn meeting, the Institute of Noise Control Engineering of Japan, 101 - 104, Japanese

  • Absorption characteristics of a microperforated panel absorber and increasing its absorption frequency range
    矢入 幹記, 阪上 公博
    日本騒音制御工学会, Sep. 2014, 公益社団法人日本騒音制御工学会秋季研究発表会講演論文集 = Proceedings of the autumn meeting, the Institute of Noise Control Engineering of Japan, 105 - 108, Japanese

  • Effect of a Porous Absorbent Layer on Absorption Characteristics of a Double-Leaf MPP Space Absorber
    OKANO Mitsuru, SAKAGAMI Kimihiro
    Architectural Institute of Japan, 24 May 2013, 日本建築学会近畿支部研究報告集. 環境系, (53) (53), 69 - 72, Japanese

  • Membrane-type Sound Absorbers and Double-leaf Permeable Membrane Space Sound Absorbers
    阪上 公博
    日本騒音制御工学会, Aug. 2012, 騒音制御, 36(4) (4), 254 - 258, Japanese

  • 4017 Evaluation of sound radiation using force radiation modes for a sound field with a reflecting surface
    ISHIBASHI Shinji, YAMAGUCHI Zenzo, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 2012, 日本建築学会近畿支部研究報告集. 環境系, (52) (52), 65 - 68, Japanese

  • 4006 An Experimental Study on Sound Absorption Characteristic of Cylindrical MPP Space Absorber with Core
    FUJITA Shota, SAKAGAMI Kimihiro, YAIRI Motoki, TOYODA Emi, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 2012, 日本建築学会近畿支部研究報告集. 環境系, (52) (52), 21 - 24, Japanese

  • 4004 A basic study on the sound transmission of a spherical wave through an elastic plate
    TSUKAMOTO Yohei, SAKAGAMI Kimihiro, YAIRI Motoki, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 2012, 日本建築学会近畿支部研究報告集. 環境系, (52) (52), 13 - 16, Japanese

  • 4016 Evaluation of Sound Radiation Using Extended Radiation Modes for a multiple element vibration structure
    MIURA Shuhei, YAMAGUCHI Zenzo, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 2011, 日本建築学会近畿支部研究報告集. 環境系, (51) (51), 61 - 64, Japanese

  • 4008 Sound absorption characteristics of a double-leaf structure composed of an MPP and a permeable membrane with a porous layer
    KOBATAKE Seiji, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 2011, 日本建築学会近畿支部研究報告集. 環境系, (51) (51), 29 - 32, Japanese

  • Devices for improving speech transmission performance - Next generation sound absorbing materials: Microperforated panels and polyester nonwovens -
    SAKAGAMI Kimihiro, FUJIMOTO Kazutoshi
    Jul. 2009, Journal of INCE/J, Vol. 33, No. 4, pp. 307-316, Japanese
    [Invited]
    Introduction scientific journal

  • Chladni Patterns
    SAKAGAMI Kimihiro
    Jun. 2009, Journal of Acoustical Society of Japan (J), Vol. 65, No. 6, p.337, Japanese
    [Invited]
    Introduction scientific journal

  • 4001 Analysis of the sound absorption characteristics of a double-leaf structure consisted of an MPP and a permeable membrane
    FUKUTANI Yusaku, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 22 May 2009, 日本建築学会近畿支部研究報告集. 環境系, (49) (49), 1 - 4, Japanese

  • Kobe Science Museum
    SAKAGAMI Kimihiro
    The Acoustical Society of Japan (ASJ), Dec. 2008, Journal of Acoustical Society of Japan (J), 64 (12) 736(12) (12), 736 - 736, Japanese
    [Invited]
    Introduction scientific journal

  • 4016 A basic study on wideband sound absorbers with a combination of MPP absorber and panel absorption
    KONDO Maiko, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 23 May 2008, 日本建築学会近畿支部研究報告集. 環境系, (48) (48), 61 - 64, Japanese

  • 4007 A Study on sound absorption characteristics of a honeycomb-backed double MPP absorber
    YAMASHITA Ippei, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 23 May 2008, 日本建築学会近畿支部研究報告集. 環境系, (48) (48), 25 - 28, Japanese

  • 4005 Sound absorption of a double-leaf microperforated-panel with an air-back cavity : Detailed discussion with a strict theory
    MATSUTANI Kiyotaka, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 23 May 2008, 日本建築学会近畿支部研究報告集. 環境系, (48) (48), 17 - 20, Japanese

  • 4013 A basic study on wideband sound absorbers with a combination of MPP absorber and porous absorber
    OKAMOTO Naoko, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 23 May 2008, 日本建築学会近畿支部研究報告集. 環境系, (48) (48), 49 - 52, Japanese

  • Speaking tubes
    SAKAGAMI Kimihiro
    The Acoustical Society of Japan (ASJ), Apr. 2008, Journal of Acoustical Society of Japan (J), 64 (4) 261(4) (4), 261 - 261, Japanese
    [Invited]
    Introduction scientific journal

  • Ringve Museum
    Sakagami, Kimihiro
    The Acoustical Society of Japan (ASJ), Feb. 2008, Journal of the Acoustical Society of Japan, Vol. 64, No. 2, p.125(2) (2), 125 - 125, Japanese
    [Invited]
    Introduction scientific journal

  • 4008 A basic study on wideband sound absorbers with a combination of two MPP absorbers
    NAGAYAMA Yoshiki, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 22 May 2007, 日本建築学会近畿支部研究報告集. 環境系, (47) (47), 29 - 32, Japanese

  • Parabolic sound reflectors
    Sakagami, Kimihiro
    The Acoustical Society of Japan (ASJ), Apr. 2007, Journal of the Acoustical Society of Japan, Vol. 63, No. 4, p.239(4) (4), 239 - 239, Japanese
    [Invited]
    Introduction scientific journal

  • Absorption properties of microperforated panel absorber
    YAIRI Motoki, SAKAGAMI Kimihiro
    The Acoustical Society of Japan (ASJ), Feb. 2007, Journal of the Acoustical Society of Japan, 63 (2)(2) (2), 76 - 82, Japanese
    [Invited]
    Introduction scientific journal

  • 4013 A basic study on the sound field analysis of periodic structures : Applicability of the analysis method using the periodic boundary condition
    FUKUWAKA Naoko, TANIGAWA Masaki, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 23 May 2006, 日本建築学会近畿支部研究報告集. 環境系, (46) (46), 49 - 52, Japanese

  • 4016 A basic study on the analysis of sound fields around periodic structures : Boundary integral equation analysis using the Green function for a periodic boundary condition
    MATSUURA Yukiko, TANIGAWA Masaki, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 23 May 2005, 日本建築学会近畿支部研究報告集. 環境系, (45) (45), 61 - 64, Japanese

  • A note on the measurements of physical measures for room acoustics evaluation : Current issues and perspective
    HANYU Toshiki, SAKAGAMI Kimihiro, SAKAMOTO Shinichi
    The Acoustical Society of Japan (ASJ), 25 Dec. 2004, The Journal of the Acoustical Society of Japan, 61(1) (1), 50 - 55, Japanese

  • 4005 A basic study on the absorption characteristics of a double-leaf microperforated panel with a rigid back wall : The effect of backing structure
    NAKAJIMA Kosuke, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 24 May 2004, 日本建築学会近畿支部研究報告集. 環境系, (44) (44), 17 - 20, Japanese

  • Effects of periodic ribs on an acoustical gain by a stage riser
    NAKANISHI S., SAKAGAMI K., MORIMOTO M.
    17 Mar. 2004, 日本音響学会研究発表会講演論文集, 2004(1) (1), 833 - 834, Japanese

  • Effect of impervious films on the absorption characteristics of porous absorbent materials
    SAKAGAMI Kimihiro, NISHIO Junko, MORIMOTO Masayuki
    17 Sep. 2003, 日本音響学会研究発表会講演論文集, 2003(2) (2), 885 - 886, Japanese

  • 多孔質吸音材による固体音の放射制御
    矢入 幹記, 阪上 公博, 森本 政之
    鹿島技術研究所, Sep. 2003, 鹿島技術研究所年報, 51, 129 - 134, Japanese

  • 4009 Effect of Impervious Films on Absorption Characteristics of a Porous Sound Absorbent
    NISHIO Junko, SAKAGAM Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 26 May 2003, 日本建築学会近畿支部研究報告集. 環境系, (43) (43), 33 - 36, Japanese

  • 4023 A basic study on absorption characteristics of double-leaf permeable membranes
    EYAMA Mai, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 26 May 2003, 日本建築学会近畿支部研究報告集. 環境系, (43) (43), 89 - 92, Japanese

  • Sound insulation performance of porous ceramic sound absorbent panels(SUMMARIES OF TECHNICAL PAPERS OF ANNUAL MEETING ARCHITECTURAL INSTITUTE OF JAPAN 2002)
    KASHIWAGI Takao, KITAYAMA Satoru, ODA Kazuo, MIYAO Nobuaki, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 30 Jun. 2002, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D-1, Environmental engineering I, Room acoustics and acoustic environment noise and solidborne sound environmental vibration light and color water supply and drainage water environment urban installation and environmental management environmental psychology and physiology environmental design electro-magnetic environment, 2002, 127 - 128, Japanese

  • Effects of surface absorption of steel plate girders on the elevated structure noise
    NAKAJIMA Noboru, SAKAGAMI Kimihiro, MORIMOTO Masayuki, MICHISHITA Kazutoshi
    Architectural Institute of Japan, 24 May 2002, 日本建築学会近畿支部研究報告集. 環境系, (42) (42), 209 - 212, Japanese

  • The reduction effect of a dynamic absorber on the structure-bome sound radiation from a double-leaf wall : A simplified analysis with one-dimensional piston vibration model
    KOIKE Wakana, YAIRI Motoki, SAKAGAMI Kimihiro, MORIMOTO Masayuki, MINEMURA Atsuo, ANDOW Kei
    Architectural Institute of Japan, 24 May 2002, 日本建築学会近畿支部研究報告集. 環境系, (42) (42), 125 - 128, Japanese

  • Effect of an interior wall on the structure-borne sound radiation from walls : Effects of a stud and its vibration isolation on the structure-borne sound radiation from double-leaf walls
    SAKAGAMI Eiji, YAIRI Motoki, SAKAGAMI Kimihiro, FUJIWARA Hiroko, MORIMOTO Masayuki, MINEMURA Atsuo, ANDOW Kei
    Architectural Institute of Japan, 24 May 2002, 日本建築学会近畿支部研究報告集. 環境系, (42) (42), 141 - 144, Japanese

  • The vibration and sound radiation of a stage floor in concert auditoria
    SAKAGAMI Kimihiro
    The Acoustical Society of Japan (ASJ), 25 Dec. 2001, The Journal of the Acoustical Society of Japan, 58(1) (1), 46 - 53, Japanese

  • A study on countermeasure for the elevated structure noise - Effect of an adjacent plate girder on the sound field and noise reduction effect of surface absorption of the plate girder -
    MICHISHITA K., YAMAGUCHI Z., SAKAGAMI K., MORIMOTO M.
    01 Oct. 2001, 日本音響学会研究発表会講演論文集, 2001(2) (2), 815 - 816, Japanese

  • Experimental study on the structure-borne sound radiation of a double-leaf wall
    YAIRI M., MINEMURA A., ANDOW K., SAKAGAMI K., MORIMOTO M.
    01 Oct. 2001, 日本音響学会研究発表会講演論文集, 2001(2) (2), 933 - 934, Japanese

  • Acoustic properties of a triple-leaf membrane: Effect of the arrangement of a permeable leaf
    SAKAGAMI K., MORIMOTO M., KIYAMA M.
    01 Oct. 2001, 日本音響学会研究発表会講演論文集, 2001(2) (2), 943 - 944, Japanese

  • Effect of an Interior-Panel on the Structure-Borne Sound Radiation
    Yairi Motoki, Sakagami Kimihiro, Morimoto Masayuki
    鹿島技術研究所, Sep. 2001, Annual report of Kajima Technical Research Institute,Kajima Corporation, 49, 127 - 132, English

  • A basic study on reduction of noise due to electromagnetic vibration
    MICHISHITA Kazutoshi, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    01 Aug. 2001, 電気設備学会全国大会講演論文集, 19, 71 - 72, Japanese

  • 4030 The effect of an interior wall on structure-borne sound radiation : The reduction effect of surface absorption and perforated interior walls
    FUJIWARA Hiroko, YAIRI Motoki, SAKAGAMI Kimihiro, SAKAGAMI Eiji, MORIMOTO Masayuki, MINEMURA Atsuo, ANDOW Kei
    Architectural Institute of Japan, 25 May 2001, 日本建築学会近畿支部研究報告集. 環境系, (41) (41), 117 - 120, Japanese

  • 4003 The reduction effect of an absorbent layer in the cavity on the sound radiation from a double-leaf structure
    IIZUKA Mina, YAIRI Motoki, SAKAGAMI Kimihiro, SAKAGAMI Eiji, MORIMOTO Masayuki, MINEMURA Atsuo, ANDOW Kei
    Architectural Institute of Japan, 25 May 2001, 日本建築学会近畿支部研究報告集. 環境系, (41) (41), 9 - 12, Japanese

  • 4023 Effects of directivity of periodic ribs on acoustic properties of a stage floor
    NAKANISHI Shinsuke, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 2001, 日本建築学会近畿支部研究報告集. 環境系, (41) (41), 89 - 92, Japanese

  • A basic study on the reduction effect of the structure-borne sound radiation from a double-leaf plate
    YAIRI M., SAKAGAMI K., MORIMOTO M., SAKAGAMI E., MINEMURA A., ANDOW K.
    01 Mar. 2001, 日本音響学会研究発表会講演論文集, 2001(1) (1), 815 - 816, Japanese

  • A Simplified Analysis of the sound radiation from a double-leaf structure with a one-dimensional piston vibration model
    Sakagami Kimihiro, Yairi Motoki, Morimoto Masayuki[et al.]
    Kobe University, Nov. 2000, Memoirs of the Faculty of Engineering, Kobe University, 47, 37 - 50, English

  • Effects of periodic ribs on acoustic properties of a stage floor -Theoretical analysis of a sound field reflected by an elastic ribbed plate with an air back cavity-
    NAKANISHI S., SAKAGAMI K., MORIMOTO M.
    01 Sep. 2000, 日本音響学会研究発表会講演論文集, 2000(2) (2), 803 - 804, Japanese

  • Variation of sound radiation reduction of an interior wall of double-leaf constructions due to excitation condition and parameters of structural wall
    YAIRI M., SAKAGAMI K., MORIMOTO M., SAKAGAMI E., MINEMURA A., ANDOW K.
    01 Sep. 2000, 日本音響学会研究発表会講演論文集, 2000(2) (2), 711 - 712, Japanese

  • Effect of a suspended barrier on the elevated structure noise
    MICHISHITA K., YAMAGUCHI Z., NAKAJIMA N., SAKAGAMI K., MORIMOTO M.
    01 Sep. 2000, 日本音響学会研究発表会講演論文集, 2000(2) (2), 579 - 580, Japanese

  • 4014 Effect of a suspended barrier on the elevated structure noise
    NAKAJIMA Noboru, MICHISHITA Kazutoshi, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 2000, 日本建築学会近畿支部研究報告集. 環境系, (40) (40), 53 - 56, Japanese

  • 4013 A basic study of the effect of interior materials on structure-borne sound : Sound radiation from an unbounded double-leaf elastic plate
    SAKAGAMI Eiji, YAIRI Motoki, SAKAGAMI Kimihiro, MORIMOTO Masayuki, MINEMURA Atsuo, ANDOW Kei
    Architectural Institute of Japan, 25 May 2000, 日本建築学会近畿支部研究報告集. 環境系, (40) (40), 49 - 52, Japanese

  • 4009 Effects of periodic ribs on acoustic properties of a stage floor
    NAKANISHI Shinsuke, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 2000, 日本建築学会近畿支部研究報告集. 環境系, (40) (40), 33 - 36, Japanese

  • Extrapolation of a Room Impulse Response Using One-Step Method
    MENG Zihou, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    01 Mar. 2000, 日本音響学会研究発表会講演論文集, 2000(1) (1), 547 - 548, English

  • Sound radiation from a double-leaf elastic plate of infinite extent with a point force excitation-A basic study on structure-borne sound radiation from an interior wall-
    YAIRI M., SAKAGAMI K., MORIMOTO M., MINEMURA A., ANDOW K.
    01 Mar. 2000, 日本音響学会研究発表会講演論文集, 2000(1) (1), 757 - 758, Japanese

  • A comparison between a rectangular elastic plate with large aspect ratio and an infinitely long elastic plate strip for the analysis of the radiated sound field
    MICHISHITA K., SAKAGAMI K., MORIMOTO M.
    01 Mar. 2000, 日本音響学会研究発表会講演論文集, 2000(1) (1), 761 - 762, Japanese

  • Effect of vibration on the acoustic properties of porous absorbent layers
    Sakagami Kimihiro, Morimoto Masayuki
    Kobe University, Nov. 1999, Memoirs of the Faculty of Engineering, Kobe University, 46, 33 - 39, English

  • An analysis of sound radiation from an I-shaped girder of motorway -the influence of reflection by a slab-
    MICHISHITA K., YAMAGUCHI Z., SAKAGAMI K., MORIMOTO M.
    01 Sep. 1999, 日本音響学会研究発表会講演論文集, 1999(2) (2), 755 - 756, Japanese

  • Theoretical analysis of the sound field reflected by an elastic circular plate in a rigid baffle.
    NAKANISHI S., SAKAGAMI K., MORIMOTO M.
    01 Sep. 1999, 日本音響学会研究発表会講演論文集, 1999(2) (2), 915 - 916, Japanese

  • Prediction of the absorption characteristics of finite size membrane absorbers.
    KIYAMA M., UYAMA T., SAKAGAMI K., MORIMOTO M.
    01 Sep. 1999, 日本音響学会研究発表会講演論文集, 1999(2) (2), 845 - 846, Japanese

  • Acoustic properties of a triple-leaf membrane:A basic study with a simple model
    SAKAGAMI K., MORIMOTO M., KIYAMA M.
    01 Sep. 1999, 日本音響学会研究発表会講演論文集, 1999(2) (2), 847 - 848, Japanese

  • 4054 Prediction of the absorption characteristics of finite size membrane absorbers
    UAYAMA Toru, SAKAGAMI Kimihiro, MORIMOTO Masayuki, KIYAMA Masakazu
    Architectural Institute of Japan, 25 May 1999, 日本建築学会近畿支部研究報告集. 環境系, (39) (39), 213 - 216, Japanese

  • 4056 Theoretical analysis of acoustic properties of a stage floor modeled by a circular elastic plate
    NAKANISHI Shinsuke, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 1999, 日本建築学会近畿支部研究報告集. 環境系, (39) (39), 221 - 224, Japanese

  • 4055 Acoustic properties of a triple-leaf membrane : A basic study with a normal incidence model
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, KIYAMA Masakazu
    Architectural Institute of Japan, 25 May 1999, 日本建築学会近畿支部研究報告集. 環境系, (39) (39), 217 - 220, English

  • 4057 Radiated sound field by a girder of an elevated structure : Sound radiation from an unbaffled elastic plate of infinite length
    MICHISHITA Kazutoshi, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 1999, 日本建築学会近畿支部研究報告集. 環境系, (39) (39), 225 - 228, Japanese

  • Sound radiation from an elastic plate strip of infinite length -Numerical analysis using the method of equivalent sources-
    MICHISHITA K., SAKAGAMI K., MORIMOTO M., SVENSSON U. Peter
    01 Mar. 1999, 日本音響学会研究発表会講演論文集, 1999(1) (1), 761 - 762, Japanese

  • Acoustic reflection of an elastic plate with periodic ribs and a back cavity
    SAKAGAMI K.
    1999, Acustica/Acta Acustica, 85, 1 - 11

  • 4030 Effects of room surfaces on the radiated sound of a kettledrum. : Numerical analysis with the equivalent source method
    NAKANO Mayumi, Svensson U. Peter, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 1998, 日本建築学会近畿支部研究報告集. 環境系, (38) (38), 117 - 120, Japanese

  • 4024 Absorption characteristics of a permeable double-leaf membrane with an absorptive layer in its cavity
    UYAMA Toru, KIYAMA Masakazu, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 1998, 日本建築学会近畿支部研究報告集. 環境系, (38) (38), 93 - 96, Japanese

  • 4023 Effect of vibration on the acoustic properties of porous absorbent layers
    SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Architectural Institute of Japan, 25 May 1998, 日本建築学会近畿支部研究報告集. 環境系, (38) (38), 89 - 92, English

  • Acoustic properties of membrane structures
    SAKAGAMI Kimihiro
    The Acoustical Society of Japan (ASJ), Jan. 1998, The Journal of the Acoustical Society of Japan, 54(1) (1), 47 - 52, Japanese

  • Experimental sytuy on the acpistic properties of permeable double-leaf members
    KIYAMA Masakazu, SAKAGAMI Kimihiro, MORIMOTO Masayuki, TAKAHASHI Daiji
    Architectural Institute of Japan, 30 Jul. 1997, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D-1, Environmental engineering I, Room acoustics and acoustic environment noise and solidborne sound environmental vibration light and color water supply and drainage water environment urban installation and environmental management environmental psychology and physiology environmental design electro-magnetic environment, 1997, 107 - 108, Japanese

  • Effects of the absorptive cavity on the acoustic properties of the elastoc plate with a point force excitation
    NAKANISHI Shinsuke, SAKAGAMI Kimihiro, MORIMOTO Masayuki, TAKAHASHI Daiji
    Architectural Institute of Japan, 30 Jul. 1997, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D-1, Environmental engineering I, Room acoustics and acoustic environment noise and solidborne sound environmental vibration light and color water supply and drainage water environment urban installation and environmental management environmental psychology and physiology environmental design electro-magnetic environment, 1997, 105 - 106, Japanese

  • 4001 Some further considerations on the acoustic properties of a permeable membrane
    SAKAGAMI Kimihiro, KIYAMA Masakazu, MORIMOTO Masayuki, TAKAHASHI Daiji
    Architectural Institute of Japan, 26 May 1997, 日本建築学会近畿支部研究報告集. 環境系, (37) (37), 1 - 4, English

  • 4002 Acoustic properties of a double-leaf membrane with an absorptive layer in its cavity
    UYAMA Toru, KIYAMA Masakazu, SAKAGAMI Kimihiro, MORIMOTO Masayuki, TAKAHASHI Daiji
    Architectural Institute of Japan, 26 May 1997, 日本建築学会近畿支部研究報告集. 環境系, (37) (37), 5 - 8, Japanese

  • Effects of absorptive layer on acoustic properties of double-leaf membrane structures.
    KIYAMA M., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Mar. 1997, 日本音響学会研究発表会講演論文集, 1997(2) (2), 889 - 890, Japanese

  • Effects of an absoptive cavity on the acoustic properties of the stage floor
    NAKANISHI S., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Mar. 1997, 日本音響学会研究発表会講演論文集, 1997(2) (2), 861 - 862, Japanese

  • Sound transmission of a single-leaf permeable membrane.
    KIYAMA M., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Sep. 1996, 日本音響学会研究発表会講演論文集, 1996(2) (2), 791 - 792, Japanese

  • Effect of an excitation force of a musical instrument on a stage floor : Some examples by model analysis with measured excitation force of a violoncello
    NAKANISHI S., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Sep. 1996, 日本音響学会研究発表会講演論文集, 1996(2) (2), 815 - 816, Japanese

  • Experimental study on excitation farce from a violoncello to a stage floor
    NAKAHISHI Shinsuke, DAIDO Masafumi, SAKAGAMI Kimihiro, MORIMOTO Masayuki, KOGA Takashi
    Architectural Institute of Japan, 30 Jul. 1996, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D-1, Environmental engineering I, Room acoustics and acoustic environment noise and solidborne sound environmental vibration light and color water supply and drainage water environment urban installation and environmental management environmental psychology and physiology environmental design electro-magnetic environment, 1996, 199 - 200, Japanese

  • Experimental study on the acoustic properties of double-leaf membranes
    KIYAMA Masakazu, SAKAGAMI Kimihiro, MORIMOTO Masayuki, TAKAHASHI Daiji
    Architectural Institute of Japan, 30 Jul. 1996, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D-1, Environmental engineering I, Room acoustics and acoustic environment noise and solidborne sound environmental vibration light and color water supply and drainage water environment urban installation and environmental management environmental psychology and physiology environmental design electro-magnetic environment, 1996, 147 - 148, Japanese

  • 40075 Detailed analysis of acoustic properties of permeable membranes
    SAKAGAMI Kimihiro, KIYAMA Masakazu, MORIMOTO Masayuki, TAKAHASHI Daiji
    Architectural Institute of Japan, 30 Jul. 1996, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D-1, Environmental engineering I, Room acoustics and acoustic environment noise and solidborne sound environmental vibration light and color water supply and drainage water environment urban installation and environmental management environmental psychology and physiology environmental design electro-magnetic environment, 1996, 149 - 150, English

  • Acoustic properties of double-leaf membranes with permeability. -Parametric studies-
    KIYAMA M., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Mar. 1996, 日本音響学会研究発表会講演論文集, 1996(2) (2), 815 - 816, Japanese

  • Acoustic properties of double-leaf membranes with permeability. -Theoretical considerations-
    KIYAMA M., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Mar. 1996, 日本音響学会研究発表会講演論文集, 1996(2) (2), 813 - 814, Japanese

  • Acoustic Radiation from a Baffled Elastic Plate Strip of Infinite Length
    Kimihiro Sakagami, Kazutoshi Michishita, masayuki Morimoto, Yasutoshi Kitamura
    Kobe University, 22 Dec. 1995, Memoirs of the Faculty of Engineering, Kobe University, 42, 13 - 27, English

  • Some considerations on sound absorption characteristics of membrane absorbers.
    KIYAMA M., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Sep. 1995, 日本音響学会研究発表会講演論文集, 1995(2) (2), 819 - 820, Japanese

  • Efects of a point excitation on an infinite elastic plate with a back cavity -A basic study on acoustic properties of stage floors : Part2-
    NAKANISHI S., DAIDO M., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Sep. 1995, 日本音響学会研究発表会講演論文集, 1995(2) (2), 879 - 880, Japanese

  • Reflection of a spherical sound wave by a cavity-backed elastic plate with a point force excitation
    NAKANISHI Shinsuke, DAIDO Masafumi, SAKAGAMI Kimihiro, MORIMOTO Masayuki, TAKAHASHI Daiji
    Architectural Institute of Japan, 20 Jul. 1995, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D-1, Environmental engineering I, Room acoustics and acoustic environment noise and solidborne sound environmental vibration light and color water supply and drainage water environment urban installation and environmental management environmental psychology and physiology environmental design electro-magnetic environment, 1995, 7 - 8, Japanese

  • Frequency dependence of auditory source width
    SETOYAMA H., SAKAGAMI K., MORIMOTO M., IIDA K.
    01 Mar. 1995, 日本音響学会研究発表会講演論文集, 1995(1) (1), 853 - 854, Japanese

  • Reflection of a spherical sound wave by an infinite elastic plate with a back cavity
    NAKANISHI S., DAIDO M., SAKAGAMI K., MORIMOTO M., TAKAHASHI D.
    01 Mar. 1995, 日本音響学会研究発表会講演論文集, 1995(1) (1), 765 - 766, Japanese

  • An Analysis of the Acoustic Properties of Double Membrane Structures
    TANIGAWA M., SAKAGAMI K., MORIMOTO M., TAKAHASHI D., KIYAMA M.
    01 Mar. 1995, 日本音響学会研究発表会講演論文集, 1995(1) (1), 807 - 808, Japanese

  • 剛バフル中の有限幅無限長弾性板による反射音場
    阪上 公博, 森本 政之, 高橋 大弐
    神戸大学, 01 Mar. 1995, 神戸大学大学院自然科学研究科紀要. B, 13, 61 - 76, Japanese

  • 弾性板の音響反射特性に関する研究(環境工学)(学位論文要旨)
    阪上 公博
    一般社団法人日本建築学会, 20 Sep. 1994, 建築雑誌. 建築年報, 1994, 130 - 130, Japanese

  • Reflection of a Spherical Sound Wave by an Elastic Plate with Point Force Excitation
    DAIDO Masafumi, SAKAGAMI Kimihiro, MORIMOTO Masayuki, TAKAHASHI Daiji
    Architectural Institute of Japan, 25 Jul. 1994, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D, Environmental engineering, 1994, 1771 - 1772, Japanese

  • Accoustic Radiation from an Elastic Plate Strip of Infinite Length
    MICHISHITA Kazutoshi, SAKAGAMI Kimihiro, MORIMOTO Masayuki, KITAMURA Yasutoshi
    Architectural Institute of Japan, 25 Jul. 1994, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D, Environmental engineering, 1994, 1595 - 1596, Japanese

  • Effects of Low Frequency Componets of Reflections on Auditory Source Width
    SETOYAMA Haruki, MORIMOTO Masayuki, SAKAGAMI Kimihiro, IIDA Kazuhiro
    Architectural Institute of Japan, 25 Jul. 1994, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D, Environmental engineering, 1994, 1719 - 1720, Japanese

  • On the numerical analysis of reflected sound field from an elastic plate using finite element and boundary element methods.
    SAKAGAMI Kimihiro, SUGIMOTO Rie, TAKAHASHI Daiji, MORIMOTO Masayuki
    本論文では、定常状態における弾性平面板による反射音場を、有限要素法及び境界要素法を用いて解析する方法について述べ、更に本解析法における板振動に対する音響負荷の取扱いについて検討を行った。その結果、放射音圧を振動方程式に逐次代入する方法により、損失係数が大きい場合には、共振点近傍でも音響負荷を評価できる可能性が示された。数値計算結果からは、板の弾性振動の影響により、板の共振点近傍に反射波のピーク及びディップが現れるだけでなく、共振点近傍以外でも弾性振動の影響が数dBになる場合が見られた。また、板の諸定数(ヤング率、密度、厚さ、損失係数)の変化による影響を明らかにした。
    The Acoustical Society of Japan (ASJ), 01 Nov. 1992, The Journal of the Acoustical Society of Japan, 48(11) (11), 786 - 793, Japanese

  • 4014 A note on the approximation of the acoustic loading for calculation of the reflected field from an elastic plate
    SAKAGAMI Kimihiro
    Architectural Institute of Japan, 02 Jun. 1992, 日本建築学会近畿支部研究報告集. 計画系, (32) (32), 53 - 56, Japanese

  • An analysis on the acoustic reflection by elastic plane plates using finite element and boundary element method
    SAKAGAMI Kimihiro
    Architectural Institute of Japan, 01 Aug. 1991, Summaries of technical papers of Annual Meeting Architectural Institute of Japan. D, Environmental engineering, 1991, 349 - 350, Japanese

  • 4002 On the acoustic reflection of an elastic rectangular plane plate : A numerical analysis using finite element and boundary element method
    SUGIMOTO Rie, SAKAGAMI Kimihiro, TAKAHASHI Daiji, MORIMOTO Masayuki, MAEKAWA Zyun-iti
    Architectural Institute of Japan, 07 May 1991, 日本建築学会近畿支部研究報告集. 計画系, (31) (31), 5 - 8, Japanese

  • 4001 An analysis on the acoustic reflection of an elastic plane plate using finite element and boundary element method : Comparison with rigorous solution in two-dimensional sound field
    SAKAGAMI Kimihiro
    Architectural Institute of Japan, 07 May 1991, 日本建築学会近畿支部研究報告集. 計画系, (31) (31), 1 - 4, Japanese

  • 弾性平面板の音響反射特性に関する基礎的考察
    阪上 公博, 前川 純一
    神戸大学, Mar. 1990, 神戸大学大学院自然科学研究科紀要. B, 8, 41 - 48, Japanese

■ Books And Other Publications
  • グラフィカルな表現法による複雑現象の理解
    神戸大学大学院工学研究科グラフィクスリテラシー教育研究センター編
    Joint editor, 編集, 神戸大学出版会, Mar. 2024, ISBN: 9784909364289

  • 建築音響
    阪上, 公博, 豊田, 政弘, 佐藤, 逸人, 羽入, 敏樹, 尾本, 章
    Others, 編集および第3章「音響材料」,「まえがき」, コロナ社, Dec. 2019, Japanese, ISBN: 9784339013634

  • 音響キーワードブック(「吸音材料」の項を担当)
    SAKAGAMI KIMIHIRO
    Others, コロナ社, Feb. 2016, Japanese
    Dictionary or encycropedia

  • 住宅の省エネルギー計画・技術指針(委員会成果報告書)
    Sakagami, Kimihiro
    Joint work, 社団法人空気調和・衛生工学会省エネルギー委員会住宅小委員会, Nov. 2007, Japanese
    Report

  • 建築・環境音響学
    前川, 純一, 森本, 政之, 阪上, 公博
    共立出版, 2000, Japanese, ISBN: 9784320076556

■ Lectures, oral presentations, etc.
  • プレナムドアの遮音性能向上に関する数値解析的検討-吸音処理とMPPの挿入による効果-
    兒玉和紗, 阪上公博
    日本音響学会秋季研究発表会, Sep. 2024, Japanese
    Poster presentation

  • 数値シミュレーションによる異形孔を有する微細穿孔板の吸音特性に関する検討
    阿部桜子, 阪上公博
    日本音響学会秋季研究発表会, Sep. 2024, Japanese
    Poster presentation

  • 不均一な背後空気層を持つ板振動型吸音体に関する基礎的研究
    千田絢理, 阪上公博
    日本音響学会秋季研究発表会, Sep. 2024, Japanese
    Poster presentation

  • 編物の吸音特性に関する基礎的研究-実験的検討-
    高橋響, 阪上公博
    日本音響学会秋季研究発表会, Sep. 2024, Japanese
    Poster presentation

  • MPPを付加した卓上パーティションの音響特性解析と最適化の試み
    片山開人, 阪上公博, 奥園健
    日本音響学会建築音響研究委員会, May 2023, Japanese
    Oral presentation

  • 並列陽的時間領域 FEM の大規模建築空間のバイノーラル可聴化への応用
    吉田卓彌, 奥園健, 阪上公博
    日本音響学会春季研究発表会, Mar. 2023, Japanese
    Oral presentation

  • クラウドコンピューティングを用いた並列陽的 FEM による室内音響解析
    吉田 卓彌, 奥園 健, 阪上 公博
    日本音響学会秋季研究発表会, Sep. 2022, Japanese
    Oral presentation

  • 意匠性の高い不均質MPP吸音体のデザインに関する基礎的研究
    阪上公博, 草鹿みどり 奥園健
    日本音響学会2022年秋季研究発表会, Sep. 2022, Japanese
    Oral presentation

  • 実験室環境における単板固定窓の遮音性能予測のための有限要素モデリングに関する検討
    三村茉莉絵, 奥園健, 阪上公博
    日本音響学会2022年秋季研究発表会, Sep. 2022, Japanese
    Oral presentation

  • 陽的時間領域有限要素法による大規模室内音響解析
    吉田 卓彌, 奥園 健, 阪上 公博
    日本音響学会建築音響研究委員会, Aug. 2022, Japanese
    Oral presentation

  • FEM による実験室環境における単板固定窓の音響透過損失の予測
    三村 茉莉絵, 奥園 健, 阪上 公博
    日本音響学会建築音響研究委員会, Aug. 2022, Japanese
    [Invited]
    Oral presentation

  • プレナム構造のドアへの適用に関する基礎的検討
    阪上公博, 奥園健, 松村宗一郎
    日本建築学会建築音響研究会, May 2022, Japanese
    Oral presentation

  • 平面波エンリッチメントを用いた FEM による 2 次元室内音響解析手法の頑健性と効率に関する検討
    奥園 健, 向江 俊一, 阪上 公博
    日本音響学会建築音響研究委員会, Apr. 2022, Japanese
    Oral presentation

  • 平面波エンリッチメントを用いたFEMによる2次元室内音響解析手法の頑健性と効率に関する検討
    奥園健, 向江俊一, 阪上公博
    日本建築学会建築音響研究会, Apr. 2022, Japanese
    Oral presentation

  • 実験室における小サイズの固定窓の遮音性能と既存理論による予測
    三村茉莉絵, 塚本陽平, 富川義弘, 奥園健, 阪上公博
    日本建築学会建築音響研究会, Mar. 2022, Japanese
    Oral presentation

  • 大規模室内音響解析のための並列陽的時間領域FEM
    吉田卓彌, 奥園健, 阪上公博
    日本音響学会2022年春季研究発表会, Mar. 2022, Japanese
    Oral presentation

  • 音響材料の波動性を考慮した時間領域FEMによる3次元音響解析-その2 微細穿孔板の拡張作用モデル-
    吉田卓彌, 奥園健, 阪上公博
    日本音響学会2022年春季研究発表会, Mar. 2022, Japanese
    Oral presentation

  • 音響材料の波動性を考慮した時間領域FEMによる3次元音響解析-その1 周波数領域FEMとの比較-
    奥園健, 吉田卓彌, 阪上公博
    日本音響学会2022年春季研究発表会, Mar. 2022, Japanese
    Oral presentation

  • 固体音の放射と空気音の透過の関係から遮音性能測定を考える
    矢入幹記, 阪上公博
    日本音響学会2022年春季研究発表会, Mar. 2022, Japanese
    [Invited]
    Invited oral presentation

  • 二重窓の遮音性能の実用的予測に関する基礎的考察(2)-予測理論提案に向けた試みー
    塚本陽平, 玉井芳, 阪上公博, 奥園健, 富川義弘
    日本音響学会2022年春季研究発表会, Mar. 2022, Japanese
    Oral presentation

  • 二重窓の遮音性能の実用的予測に関する基礎的考察(1)-既存理論の適用の検討ー
    塚本陽平, 玉井芳, 阪上公博, 奥園健, 富川義弘
    日本音響学会2022年春季研究発表会, Mar. 2022, Japanese
    Oral presentation

  • プレナム構造のドアへの適用に関する基礎的検討-実大ドア模型による実験的検討-
    阪上公博, 松村宗一郎, 奥園健
    日本音響学会2022年春季研究発表会, Mar. 2022, Japanese
    Oral presentation

  • 修正アダムス法を用いた陽的時間領域FEMによる室内音場解析-周波数依存のインピーダンス境界の実装-
    杉本優衣, 吉田卓彌, 奥園健, 阪上公博
    日本建築学会建築音響研究会, Nov. 2021, Japanese
    Oral presentation

  • 波動音響解析に基づく室内音響データベース構築に関する基礎検討-会議室を対象とした吸音効果の可聴化-
    奥園健, 吉田卓彌, 阪上公博
    日本建築学会建築音響研究会, Sep. 2021, Japanese
    Oral presentation

  • 多孔質仕切りによる単一MPP吸音体の性能向上に関する数値解析的検討
    岡山優生, 奥園健, 阪上公博
    日本音響学会2021年秋季研究発表会, Sep. 2021, Japanese
    Oral presentation

  • 修正アダムス法を用いた陽的時間領域FEMによる室内音場解析-周波数依存の吸音境界の実装-
    杉本優衣, 吉田卓彌, 奥園健, 阪上公博
    日本音響学会2021年秋季研究発表会, Sep. 2021, Japanese
    Oral presentation

  • Partitio of Unity FEM による室内音場解析-頑健な平面波数の設定に関する検討-
    向江俊一, 奥園健, 阪上公博
    日本音響学会2021年秋季研究発表会, Sep. 2021, Japanese
    Oral presentation

  • An explicit time-domain FEM for acoustic simulation in rooms with frequency-dependent impedance boundary: Comparison of performance in 2D simulation with frequency-domain FEM
    Takumi Yoshida, Takeshi Okuzono, Kimihiro Sakagami
    Internoise 2021, Aug. 2021, English
    Oral presentation

  • 時間領域FEMによる周波数依存の吸音境界を含む室内音場解析-周波数領域FEMとの比較-
    奥園健, 吉田卓彌, 阪上公博
    日本建築学会建築音響研究会, Mar. 2021, Japanese
    Oral presentation

  • アクリルパーティションへのMPPの応用
    草鹿みどり, 阪上公博, 奥園健, 山口大地, 城戸重幸
    日本音響学会, Mar. 2021, Japanese
    Oral presentation

  • ドアに対するプレナム構造の適用に関する簡易実験
    阪上公博, 奥園健, 村田遥, 田丸加奈子, 坪倉正佳, 草鹿みどり, 向江俊一
    日本音響学会, Mar. 2021, Japanese
    Oral presentation

  • Partition of Unity FEMによる3次元室内音場解析に関する基礎的研究
    田丸加奈子, 奥園健, 向江俊一, 阪上公博
    日本音響学会, Mar. 2021, Japanese
    Oral presentation

  • Partition of Unity FEMによる室内音場解析-従来FEMとの計算コストの比較-
    奥園健, 阪上公博
    日本音響学会, Mar. 2021, Japanese
    Oral presentation

  • 分散誤差を最適化した陽的時間領域FEMによる室内音響ソルバー
    吉田卓彌, 奥園健, 阪上公博
    日本音響学会, Mar. 2021, Japanese
    Oral presentation

  • 単板ガラス窓の遮音性能の実用的予測式の構築(2)
    玉井芳, 阪上公博, 奥園健, 塚本陽平
    日本音響学会, Mar. 2021, Japanese
    Oral presentation

  • 単板ガラス窓の遮音性能の実用的予測式の構築(1)
    塚本陽平, 玉井芳, 阪上公博, 奥園健
    日本音響学会, Mar. 2021

  • Partition of Unity FEMによる不均質なMPP吸音体の吸音特性の予測
    向江俊一, 奥園健, 草鹿みどり, 田丸加奈子, 阪上公博
    日本音響学会, Mar. 2021, Japanese
    Oral presentation

  • 空気音透過と固体音放射の関係-リブを有する無限大弾性板の場合-
    村田遥, 阪上公博, 奥園健, 矢入幹記, 豊田政弘
    日本音響学会建築音響研究会, Nov. 2020, Japanese
    Oral presentation

  • 不均質MPPの吸音特性と予測手法について-孔径あるいは開孔率が一定でない場合-
    草鹿みどり, 阪上公博, 奥園健, 城戸重幸, 山口大地
    日本音響学会建築音響研究会, Sep. 2020, Japanese
    Oral presentation

  • Basic study on prediction of sound insulation performance of a single-leaf window
    Tsukamoto Yohei, Sakagami Kimihiro, Okuzono, Takeshi Tomikawa Yoshihiro
    日本音響学会建築音響研究会, Jul. 2020, Japanese
    Oral presentation

  • Effect of deviation of the parameters by manufacturing accuracy of an MPP on its acoustic properties: Trial production of MPPs of various hole shapes by 3D printing
    Sakagami Kimihiro, Kusaka Midori Okuzono, Takeshi Nakanishi shinsuke
    日本音響学会建築音響研究会, Jun. 2020, Japanese
    Oral presentation

  • Measurement of the sound absorption characteristics of a spherical MPP space sound absorber
    Kimihiro Sakagami, Midori Kusaka, Takeshi Okuzono, Shigeyuki Kido, Daichi Yamaguchi
    日本音響学会建築音響研究会, Apr. 2020, Japanese
    Oral presentation

  • 有限弾性板における空気音透過と点加振放射の関係:数値解析による検討
    阪上 公博, 高橋和俊, 奥園健, 矢入幹記
    日本音響学会騒音振動研究会, Sep. 2019, Japanese, Domestic conference
    Oral presentation

  • 有限要素法による二重窓の遮音性能予測に向けた基礎検討-窓サイズの影響評価-
    三村茉莉絵, 塚本陽平, 富川義弘, 奥園健, 阪上公博
    日本音響学会建築音響研究会, Aug. 2019, Japanese, Domestic conference
    Oral presentation

  • ハニカムコアを充填した軽量二重壁の遮音特性に関する基礎的研究
    村田遥, 奥園健, 阪上公博
    日本建築学会近畿支部研究発表会, Jun. 2019, Japanese, Domestic conference
    Oral presentation

  • 背後ハニカム構造およびアレイ構造を有する単一通気性膜吸音体のモデル化に関する基礎的研究-粘性と熱伝導を考慮した理論解析-
    坪倉正佳, 奥園健, 阪上 公博
    日本建築学会近畿支部研究発表会, Jun. 2019, Japanese, Domestic conference
    Oral presentation

  • 等価流体モデルに基づく高性能吸音要素の誤差特性に関する研究
    田丸加奈子, 奥園健, 阪上公博
    日本建築学会近畿支部研究発表会, Jun. 2019, Japanese, Domestic conference
    Oral presentation

  • A discussion on finite element model of MPP using absorption elements based on an equivalent fluid
    OKUZONO TAKESHI, NITTA TAKAO, SAKAGAMI KIMIHIRO
    日本音響学会2019年春季研究発表会, Mar. 2019, Japanese, Domestic conference
    Oral presentation

  • 通気性膜吸音体アレイの垂直入射吸音特性に関する検討 –背後構造による吸音の考慮–
    OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会2019年春季研究発表会, Mar. 2019, Japanese, Domestic conference
    Oral presentation

  • 修正Adams法を用いた時間領域有限要素法による室内音場解析-離散化誤差特性の解析
    YOSHIDA TAKUMI, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会2019年春季研究発表会, Mar. 2019, Japanese, Domestic conference
    Oral presentation

  • 等価流体モデルに基づく吸音要素の分散誤差低減
    OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本建築学会大会, Sep. 2018, Japanese, Domestic conference
    Oral presentation

  • 室内音場解析のための一階常微分方程式に基づく時間領域有限要素法
    YOSHIDA TAKUMI, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会2018年秋季研究発表会, Sep. 2018, Japanese, Domestic conference
    Oral presentation

  • Microperforated panels (MPPs) as "Next-generation sound absorbing material": How to use and install them
    SAKAGAMI KIMIHIRO
    Acoustical Society of Japan Autumn Meeting 2018, Sep. 2018, Japanese, Acoustical Society of Japan, Oita University, Domestic conference
    [Invited]
    Invited oral presentation

  • 一階常微分方程式に基づく時間領域有限要素法の吸音予測精度の改善
    YOSHIDA TAKUMI, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会2018年秋季研究発表会, Sep. 2018, Japanese, Domestic conference
    Oral presentation

  • 背後ハニカム構造を有するMPP 吸音体による室内音環境改善 -小会議室における実装実験-
    SAKAGAMI KIMIHIRO, OKUZONO TAKESHI, YAIRI MOTOKI, HANYU TOSHIKI, HOSHI KAZUMA, HARADA SHINJI, TAKAHASHI SEIJI, UEDA YASUTAKA
    平成30年度日本建築学会 近畿支部研究発表会, Jun. 2018, Japanese, Domestic conference
    Oral presentation

  • 等価流体モデルに基づく吸音要素の分散誤差低減
    OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会6月度建築音響研究会, Jun. 2018, Japanese, Domestic conference
    Oral presentation

  • 等価流体モデルに基づく吸音要素の分散誤差低減
    OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    平成30年度日本建築学会近畿支部研究発表会, Jun. 2018, Japanese, Domestic conference
    Oral presentation

  • 通気性膜付き穿孔薄板を用いた吸音体の吸音特性に関する研究
    新田尭央, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO, 上幹実
    日本音響学会2018年春季研究発表会, Mar. 2018, Japanese, Domestic conference
    Oral presentation

  • 通気性膜吸音体アレイの残響室法吸音率–従来吸音体との比較–
    OKUZONO TAKESHI, 上西宏治, SAKAGAMI KIMIHIRO, 清水ひかる
    日本音響学会2018年春季研究発表会, Mar. 2018, Japanese, Domestic conference
    Oral presentation

  • 単一通気性膜吸音体の残響室法吸音率の数値予測
    清水徳泰, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会2018年春季研究発表会, Mar. 2018, Japanese, Domestic conference
    Oral presentation

  • An experimental research for sound transmission through double windows with porous absorbent materials
    TSUKAMOTO YOHEI, TOMIKAWA YOSHIHIRO, MAIKAWA HIDETOSHI, KOMOTO YUSUKE, SAKAGAMI KIMIHIRO
    日本音響学会建築音響研究会, Jan. 2018, Japanese, 東京, Domestic conference
    Oral presentation

  • 有限弾性板による空気音透過と固体音放射の関係-単純な条件下における解析的検討-
    高橋克俊, 矢入幹記, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO, 豊田政弘
    日本音響学会2017年秋季研究発表会, Sep. 2017, Japanese, Domestic conference
    Poster presentation

  • 通気性膜吸音体を有する音場解析のための一階常微分方程式に基づく時間領域有限要素法-反復法の局所的適用による計算効率化-
    吉田卓彌, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会2017年秋季研究発表会, Sep. 2017, Japanese, Domestic conference
    Oral presentation

  • 通気性膜吸音体アレイの吸音特性に関する実験的検討
    上西宏治, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会2017年秋季研究発表会, Sep. 2017, Japanese, Domestic conference
    Oral presentation

  • 一階常微分方程式に基づく時間領域有限要素法による室内音場解析-時空間離散化誤差の数値解析-
    吉田卓彌, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会2017年秋季研究発表会, Sep. 2017, Japanese, Domestic conference
    Oral presentation

  • Acoustic improvement of a small meeting room using a honeycomb-backed MPP sound absorbing system
    HOSHI KAZUMA, HANYU TOSHIKI, SAKAGAMI KIMIHIRO, YAIRI MOTOKI, OKUZONO TAKESHI, HARADA SHINJI, TAKAHASHI SEIJI, UEDA YASUTAKA
    日本音響学会建築音響研究会, Aug. 2017, Japanese, 日本音響学会, 東京, Domestic conference
    Oral presentation

  • 波動音響数値解析における微細穿孔板吸音体のモデル化-拡張作用モデルと表面インピーダンスモデルの比較-
    OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    2017年度日本建築学会大会, Aug. 2017, Japanese, Domestic conference
    [Invited]
    Invited oral presentation

  • A pilot study on the sound absorption characteristics of permeable membrane sound absorbers in cylindrical PCCC shell shape
    SAKAGAMI KIMIHIRO, SHINMA AKITAKA, OKUZONO TAKESHI, FUNAHASHI KOTA, TOYODA MASAHIRO, SUZUKI HIROTAKA, KOYANAGI NAO
    日本音響学会建築音響研究会, Aug. 2017, Japanese, 日本音響学会, 東京, Domestic conference
    Oral presentation

  • 有限弾性板による空気音透過と固体音放射の関係に関する基礎的研究
    高橋克俊, 矢入幹記, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO, 豊田政弘
    平成29年度日本建築学会近畿支部発表会, Jun. 2017, Japanese, Domestic conference
    Oral presentation

  • 数値残響室による通気性膜吸音体の吸音特性の予測に関する基礎的研究
    清水徳泰, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    平成29年度日本建築学会近畿支部発表会, Jun. 2017, Japanese, Domestic conference
    Oral presentation

  • 局所作用性MPP吸音体の吸音特性のin-situ測定
    新田尭央, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    平成29年度日本建築学会近畿支部発表会, Jun. 2017, Japanese, Domestic conference
    Oral presentation

  • 通気性膜吸音体アレイの吸音メカニズムに関する有限要素解析
    UENISHI Koji, OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会2017年春季研究発表会, Mar. 2017, Japanese, 明治大学, Domestic conference
    Oral presentation

  • 小規模矩形室に設置した MPP 吸音体の吸音効果に関する有限要素解析
    OKUZONO Takeshi, IZUMI Shugo, SAKAGAMI Kimihiro
    日本音響学会2017年春季研究発表会, Mar. 2017, Japanese, 明治大学, Domestic conference
    Oral presentation

  • 一階常微分方程式に基づく3次元時間領域有限要素解析による通気性膜吸音体の取り扱い
    YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会2017年春季研究発表会, Mar. 2017, Japanese, 明治大学, Domestic conference
    Oral presentation

  • MPP 吸音体の吸音特性の in-situ 測定に関する研究–局所作用性材料を対象 とした検討–
    OKUZONO Takeshi, SAKAGAMI Kimihiro, NITTA Takao
    日本音響学会2017年春季研究発表会, Mar. 2017, Japanese, 明治大学, Domestic conference
    Oral presentation

  • 通気性膜吸音体アレイの吸音特性に関する有限要素解析
    UENISHI Koji, OKUZONO Takeshi, SAKAGAMI Kimihiro
    騒音・振動研究会, Jan. 2017, Japanese, 神戸大学, Domestic conference
    Oral presentation

  • Limp microperforated panel finite elements and its application
    OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    5th Joint Meeting of the Acoustical Society of America and the Acoustical Society of Japan, Dec. 2016, English, International conference
    [Invited]
    Invited oral presentation

  • Use of smartphones for introductory acoustics education
    SAKAGAMI Kimihiro, SATOH Fumiaki, OMOTO Akira
    5th Joint Meeting of the Acoustical Society of America and the Acoustical Society of Japan, Nov. 2016, English, Hilton Hawaiian Village Waikiki Beach Resort, International conference
    [Invited]
    Invited oral presentation

  • Three-dimensional space sound absorbers using microperforated panels
    SAKAGAMI Kimihiro, TOYODA Masahiro, YAIRI Motoki, OKUZONO Takeshi
    5th Joint Meeting of the Acoustical Society of America and the Acoustical Society of Japan, Nov. 2016, English, Hilton Hawaiian Village Waikiki Beach Resort, International conference
    [Invited]
    Invited oral presentation

  • Numerical study on the absorption performance of MPP sound absorber installed in small rectangular rooms
    OKUZONO Takeshi, SAKAGAMI Kimihiro
    5th Joint Meeting of the Acoustical Society of America and the Acoustical Society of Japan, Nov. 2016, English, Hilton Hawaiian Village Waikiki Beach Resort, International conference
    [Invited]
    Invited oral presentation

  • 吸音材料のおはなし-音を吸収するしくみのいろいろ
    SAKAGAMI Kimihiro
    第10回KOBE工学サミット in Tokyo, Oct. 2016, Japanese, 神戸大学工学振興会, 東京六甲クラブ, Domestic conference
    Public discourse

  • MPP 吸音体を有する室内音場の 3 次元有限要素解析
    OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会2016年秋季研究発表会, Sep. 2016, Japanese, 富山大学, Domestic conference
    Oral presentation

  • 通気性膜吸音体を取り扱うための 1 階常微分方程式に基づく時間領域有限要素法
    YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    2016年度日本建築学会大会, Aug. 2016, Japanese, 福岡大学, Domestic conference
    Oral presentation

  • 矩形室に設置した MPP 吸音体の吸音効果に関する数値解析的検討
    IZUMI Shugo, OKUZONO Takeshi, SAKAGAMI Kimihiro
    2016年度日本建築学会大会, Aug. 2016, Japanese, 福岡大学, Domestic conference
    Oral presentation

  • 通気性膜吸音体の時間領域有限要素モデルの開発
    KATSUYAMA Akihiro, OKUZONO Takeshi, SAKAGAMI Kimihiro
    平成28年度日本建築学会 近畿支部研究発表会, Jun. 2016, Japanese, 大阪工業技術専門学校, Domestic conference
    Oral presentation

  • 通気性膜アレイの吸音特性に関する数値解析的研究
    UENISHI Koji, OKUZONO Takeshi, SAKAGAMI Kimihiro
    平成28年度日本建築学会 近畿支部研究発表会, Jun. 2016, Japanese, 大阪工業技術専門学校, Domestic conference
    Oral presentation

  • 1階常微分方程式に基づく時間領域有限要素解析による室内音場解析-通気性膜吸音体のモデル化-
    YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    建築音響研究会, Jun. 2016, Japanese, 東京大学生産技術研究所, Domestic conference
    Oral presentation

  • 通気性膜吸音体の吸音特性予測のための時間領域有限要素解析手法
    OKUZONO Takeshi, SAKAGAMI Kimihiro, KATSUYAMA Akihiro
    日本音響学会2016年春季研究発表会, Mar. 2016, Japanese, 横浜市, Domestic conference
    Oral presentation

  • 通気性膜アレイの吸音特性に関する数値解析的検討
    OKUZONO Takeshi, SAKAGAMI Kimihiro, UENISHI Koji
    日本音響学会2016年春季研究発表会, Mar. 2016, Japanese, 横浜市, Domestic conference
    Oral presentation

  • 固体音の放射と空気音の透過の関係‐単層無限大弾性板による基礎的検討‐
    YAIRI Motoki, NISHIBARA Kousuke, SAKAGAMI Kimihiro, OKUZONO Takeshi
    日本音響学会2016年春季研究発表会, Mar. 2016, Japanese, 横浜市, Domestic conference
    Oral presentation

  • 吸音材料のおはなし~音を吸収するしくみのいろいろ
    SAKAGAMI KIMIHIRO, YAIRI MOTOKI
    日本音響学会春季研究発表会, Mar. 2016, Japanese, 日本音響学会, 横浜, Domestic conference
    [Invited]
    Invited oral presentation

  • 吸音を有する室内音場解析のための安定的な陽的時間領域有限要素法
    YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会2016年春季研究発表会, Mar. 2016, Japanese, 横浜市, Domestic conference
    Oral presentation

  • An explicit time-domain finite element method for room acoustics simulations with frequency-independent finite impedance boundary
    OKUZONO Takeshi, YOSHIDA Takumi, SAKAGAMI Kimihiro, OTSURU Toru
    日本音響学会建築音響研究会, Dec. 2015, Japanese, 舞鶴市, Domestic conference
    Oral presentation

  • 陽的時間領域有限要素法による室内音場解析–分散誤差の理論解析–
    OKUZONO Takeshi, SAKAGAMI Kimihiro, YOSHIDA Takumi
    日本音響学会2015年秋季研究発表会, Sep. 2015, Japanese, 会津若松市, Domestic conference
    Oral presentation

  • 微細穿孔板(MPP)を用いた空間吸音体
    SAKAGAMI KIMIHIRO, YAIRI MOTOKI, TOYODA MASAHIRO
    日本騒音制御工学会研究発表会, Sep. 2015, Japanese, 日本騒音制御工学会, 東京, Domestic conference
    [Invited]
    Invited oral presentation

  • 多孔質材を充填した立体型MPP空間吸音体の吸音特性-その2 数値解析による理論的検討-
    TOYODA Masahiro, OKANO Mitsuru, OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会2015年秋季研究発表会, Sep. 2015, Japanese, 会津若松市, Domestic conference
    Oral presentation

  • 多孔質材を充填した立体型MPP空間吸音体の吸音特性-その1 実験的検討-
    SAKAGAMI Kimihiro, OKANO Mitsuru, OKUZONO Takeshi, TOYODA Masahiro, TOYODA Emi
    日本音響学会2015年秋季研究発表会, Sep. 2015, Japanese, 会津若松市, Domestic conference
    Oral presentation

  • 建築音環境予測への有限要素法の適用–計算効率化手法–
    OKUZONO Takeshi, OTSURU Toru, TOMIKU Reiji, OKAMOTO Noriko, SAKAGAMI Kimihiro
    日本音響学会2015年秋季研究発表会, Sep. 2015, Japanese, 会津若松市, Domestic conference
    [Invited]
    Invited oral presentation

  • Relationship between the field incidence sound transmission coefficient and radiated sound power driven by a point force of an elastic plate with infinite extent
    YAIRI MOTOKI, NISHIBARA KOSUKE, OKUZONO TAKESHI, SAKAGAMI KIMIHIRO
    日本音響学会建築音響研究会, Aug. 2015, Japanese, 日本音響学会建築音響研究委員会, 東京, Domestic conference
    Oral presentation

  • 陽的時間領域有限要素法による室内音場解析-長方形要素に対する修正積分則-
    YOSHIDA Takumi, OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本建築学会平成27年度近畿支部研究発表会, Jun. 2015, Japanese, 大阪市, Domestic conference
    Oral presentation

  • 単一 MPP 吸音体を有する室内音場の有限要素解析-メッシュの空間分解能と吸音モデリングに関する検討-
    IZUMI Shugo, OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本建築学会平成27年度近畿支部研究発表会, Jun. 2015, Japanese, 大阪市, Domestic conference
    Oral presentation

  • 固体放射音のパワー測定による壁体の遮音性能の評価に関する基礎的研究
    NISHIBARA Kousuke, YAIRI Motoki, SAKAGAMI Kimihiro, OKUZONO Takeshi
    日本建築学会平成27年度近畿支部研究発表会, Jun. 2015, Japanese, 大阪市, Domestic conference
    Oral presentation

  • MPP 吸音構造を有する室内音場の有限要素解析 –剛壁を有する単一 MPP 吸音構造の場合–
    OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会春季研究発表会, Mar. 2015, Japanese, 中央大学, Domestic conference
    Oral presentation

  • 陽的時間領域有限要素法による室内音場解析
    OKUZONO Takeshi, OTSURU Toru, SAKAGAMI Kimihiro
    日本音響学会秋季研究発表会, Sep. 2014, Japanese, 北海学園大学, Domestic conference
    Oral presentation

  • 微細穿孔板を有する室内音場の周波数領域有限要素解析
    OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会秋季研究発表会, Sep. 2014, Japanese, 北海学園大学, Domestic conference
    Oral presentation

  • Absorption characteristics of a microperforated panel absorber and increasing its absorption frequency range
    YAIRI MOTOKI, SAKAGAMI KIMIHIRO
    日本騒音制御工学会秋季研究発表会, Sep. 2014, Japanese, 日本騒音制御工学会, 東京, Domestic conference
    [Invited]
    Invited oral presentation

  • Applications of the next-generation sound absorbing materials: Microperforated panels (MPP) and permeable membrane
    SAKAGAMI KIMIHIRO, YAIRI MOTOKI
    日本騒音制御工学会秋季研究発表会, Sep. 2014, Japanese, 日本騒音制御工学会, 東京, Domestic conference
    [Invited]
    Invited oral presentation

  • 微細穿孔板を有する音場解析のための有限要素定式化-等価電気回路理論および波動理論との比較-
    OKUZONO Takeshi, SAKAGAMI Kimihiro
    日本音響学会建築音響研究会, Aug. 2014, Japanese, サテライトキャンパス広島, Domestic conference
    Oral presentation

  • 通気性膜を用いた立体型空間吸音体の吸音特性に関する基礎的研究
    FUNAHASHI KOTA, NISHIKAWA CHINAMI, SAKAGAMI KIMIHIRO, TOYODA MASAHIRO
    日本音響学会建築音響研究会, Jul. 2014, Japanese, 日本音響学会建築音響研究委員会, 京都, Domestic conference
    Oral presentation

  • A basice study on the absorption characteristics of a three-dimensional permeable membrane space sound absorber
    FUNAHASHI KOTA, NISHIKAWA CHINAMI, SAKAGAMI KIMIHIRO, TOYODA MASAHIRO
    日本建築学会近畿支部研究発表会, Jun. 2014, Japanese, 日本建築学会近畿支部, 大阪, Domestic conference
    Oral presentation

  • 加振力放射モードを用いた固体放射音の性状予測と制御
    石橋 慎司, 山口 善三, SAKAGAMI KIMIHIRO
    日本音響学会建築音響研究会, Nov. 2013, Japanese, 日本音響学会建築音響研究委員会, 大阪市, Domestic conference
    Oral presentation

  • 立体型MPP空間吸音体に関する基礎的研究-その2 数値解析による理論的検討-
    豊田 政弘, 小畠 星司, SAKAGAMI KIMIHIRO
    日本音響学会秋季研究発表会, Sep. 2013, Japanese, 日本音響学会, 豊橋市, Domestic conference
    Oral presentation

  • 立体型MPP空間吸音体に関する基礎的研究-その1 実験的検討-
    SAKAGAMI KIMIHIRO, 矢入 幹記, 豊田 恵美, 豊田 政弘
    日本音響学会秋季研究発表会, Sep. 2013, Japanese, 日本音響学会, 豊橋市, Domestic conference
    Oral presentation

  • 加振力放射モードを用いた個体放射音提言の検討 自由音場に存在する構造物の場合
    石橋 慎司, 山口 善三, SAKAGAMI KIMIHIRO
    日本音響学会秋季研究発表会, Sep. 2013, Japanese, 日本音響学会, 豊橋市, Domestic conference
    Poster presentation

  • 2重MPP空間吸音体の吸音特性に対する多孔質吸音層の影響
    岡野 充, SAKAGAMI KIMIHIRO, 矢入 幹記
    日本音響学会建築音響研究会, Jul. 2013, Japanese, 日本音響学会建築音響研究委員会, 京都市, Domestic conference
    Oral presentation

  • 単一板に対する球面波入射の音響透過に関する実験的検討
    塚本 陽平, 矢入 幹記, 中川 博, SAKAGAMI KIMIHIRO
    日本音響学会建築音響研究会, Jul. 2013, Japanese, 日本音響学会建築音響研究委員会, 京都市, Domestic conference
    Oral presentation

  • 2重MPP空間吸音体の吸音特性に対する多孔質吸音層の影響
    岡野 充, SAKAGAMI KIMIHIRO
    日本建築学会近畿支部研究発表会, Jun. 2013, Japanese, 日本建築学会近畿支部, 大阪市, Domestic conference
    Oral presentation

  • 立体型MPP空間吸音体に関する実験的研究
    SAKAGAMI KIMIHIRO, 矢入 幹記, 豊田 恵美, 豊田 政弘
    日本音響学会建築音響研究会, May 2013, Japanese, 日本音響学会建築音響研究委員会, 広島市, Domestic conference
    Oral presentation

  • 立体型MPP空間吸音体に関する解析的研究
    豊田 政弘, 小畠 星司, SAKAGAMI KIMIHIRO
    日本音響学会建築音響研究会, May 2013, Japanese, 日本音響学会建築音響研究委員会, 広島市, Domestic conference
    Oral presentation

  • 建築音響学の講義や演習におけるスマートフォンの利用
    SATOH FUMIAKI, SAKAGAMI KIMIHIRO, OMOTO AKIRA
    日本音響学会2013年春季研究発表会, Mar. 2013, Japanese, 東京都八王子市, Domestic conference
    Oral presentation

  • 加振力放射モードを用いた固体放射音低減の検討-反射面の影響を考慮した場合-
    ISHIBASHI SHINJI, YAMAGUCHI ZENZO, SAKAGAMI KIMIHIRO, MORIMOTO MASAYUKI
    日本音響学会2012年秋季研究発表会, Sep. 2012, Japanese, 長野市, Domestic conference
    Poster presentation

  • スマートフォンを利用した音環境導入教育の試み
    SAKAGAMI KIMIHIRO, SATOH FUMIAKI, OMOTO AKIRA
    日本音響学会2012年秋季研究発表会, Sep. 2012, Japanese, 長野市, Domestic conference
    Oral presentation

  • 微細穿孔板(MPP)を利用した空間吸音体の提案とその音響特性
    SAKAGAMI KIMIHIRO
    日本音響学会建築音響研究会, Jul. 2012, Japanese, 京都市, Domestic conference
    [Invited]
    Invited oral presentation

  • 円筒型MPP空間吸音体の吸音特性に関する実験的研究-内部に円筒状の芯を入れた場合-
    FUJITA SHOTA, SAKAGAMI KIMIHIRO, YAIRI MOTOKI, TOYODA EMI, MORIMOTO MASAYUKI
    日本音響学会建築音響研究会, Jul. 2012, Japanese, 京都市, Domestic conference
    Oral presentation

  • 球面波入射に対する単一板の音響透過に関する基礎的研究
    TSUKAMOTO YOHEI, SAKAGAMI KIMIHIRO, YAIRI MOTOKI, MORIMOTO MASAYUKI
    日本建築学会近畿支部研究発表会, Jun. 2012, Japanese, Domestic conference
    Oral presentation

  • 加振力放射モードを用いた音響放射パワの評価-反射面による影響を考慮した場合-
    ISHIBASHI SHINJI, YAMAGUCHI ZENZO, SAKAGAMI KIMIHIRO, MORIMOTO MASAYUKI
    日本建築学会近畿支部研究発表会, Jun. 2012, Japanese, 大阪市, Domestic conference
    Oral presentation

  • 円筒型MPP空間吸音体の吸音特性に関する実験的研究-内部に円筒状の芯を入れた場合-
    FUJITA SHOTA, SAKAGAMI KIMIHIRO, YAIRI MOTOKI, TOYODA EMI, MORIMOTO MASAYUKI
    日本建築学会近畿支部研究発表会, Jun. 2012, Japanese, 大阪市, Domestic conference
    Oral presentation

  • Experimental study on reduction of sound radiation from vibrating structure: deliberation of force radiation study on reduction of sound radiation from vibrating structure: deliberation of force radiation modes
    Yamaguchi Zenzo, Sakagami Kimihiro, Morimoto Masayuki, Bolton J Stuart
    Spring meeting of ASJ, Mar. 2012, Japanese, 日本音響学会, Yokohama, Domestic conference
    Oral presentation

  • A case study of introductory teaching method for environmental acoustics using a smartphone
    Sakagami Kimihiro, Satoh Fumiaki, Omoto Akira
    Techinical Committee of Architectural Acoustics, ASJ, Mar. 2012, Japanese, 日本音響学会建築音響研究委員会, Osaka, Domestic conference
    Oral presentation

  • Reduction of sound radiation by using dynamic absorber: Deliberation of force radiation modes (Part 2)
    Yamaguchi Zenzo, Matsuoka Hidetoshi, Sakagami Kimihiro, Morimoto Masayuki, Bolton J Stuart, Yamagiwa Ichiro
    Techinical Committee of Architectural Acoustics, ASJ, Oct. 2011, Japanese, 日本音響学会建築音響研究委員会, Tokyo, Domestic conference
    Oral presentation

  • Sound absorption characteristics of a microperforated panel absorber backed by a porous layer - The effect of the treatment of the end correction of a perforation -
    Kobatake Seiji, Sakagami Kimihiro, Morimoto Masayuki, Yairi Motoki
    Techinical Committee of Architectural Acoustics, ASJ, Aug. 2011, Japanese, 日本音響学会建築音響研究委員会, Kyoto, Domestic conference
    Oral presentation

  • Evalluation of sound radiatio by using force radiation modes: application to a two-member structure
    Miura Shuhei, Yamaguchi Zenzo, Sakagami Kimihiro, Morimoto Masayuki
    Techinical Committee of Architectural Acoustics, ASJ, Aug. 2011, Japanese, 日本音響学会建築音響研究委員会, Kyoto, Domestic conference
    Oral presentation

  • Evaluation of sound radiation using extended radiation modes for a multiple lelment vibration structure
    Miura Shuhei, Yamaguchi Zenzo, Sakagami Kimihiro, Morimoto Masayuki
    日本建築学会近畿支部研究発表会, Jun. 2011, Japanese, 日本建築学会近畿支部, Osaka, Domestic conference
    Oral presentation

  • Sound absorption characteristics of a double-leaf structure composed of an MPP and a permeable membrane with a porous layer
    Kobatake Seiji, Sakagami Kimihiro, Morimoto Masayuki
    日本建築学会近畿支部研究発表会, Jun. 2011, Japanese, 日本建築学会近畿支部, Osaka, Domestic conference
    Oral presentation

  • A basic study on a cylindrical MPP space sound absorber (CMSA)
    Sakagami Kimihiro, Oshitani Takayuki, Yairi Motoki, Toyoda Emi, Morimoto Masayuki
    Techinical Committee of Architectural Acoustics, ASJ, Apr. 2011, Japanese, 日本音響学会建築音響研究委員会, Tokyo, Domestic conference
    Oral presentation

  • Reduction of sound radiation by using dynamic absorber: Deliberation of force radiation modes
    YAMAGUCHI Zenzo, MATSUOKA Hidetoshi, SAKAGAMI Kimihiro, MORIMOTO Masayuki, BOLTON Stuart J, YAMAGIWA Ichiro
    2011 Spring Meeting, Acoutical Society of Japan, Mar. 2011, Japanese, 日本音響学会, Tokyo, Domestic conference
    Oral presentation

  • Reduction of sound radiation by using dynamic absorber: Deliberation of force radiation modes
    MATSUOKA Hidetoshi, YAMAGUCHI Zenzo, SAKAGAMI Kimihiro, MORIMOTO Masayuki, BOLTON Stuart J, YAMAGIWA Ichiro
    Technical Committee on Architectural Acoustics, Acoustical Society of Japan, Oct. 2010, Japanese, 日本音響学会建築音響研究委員会, Kyoto, Domestic conference
    Oral presentation

  • The effect of permeable membrane into an air cavity of DLMPP
    FUKUTANI Yusaku, SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    Technical Committee on Architectural Acoustics, Acoustical Society of Japan, Oct. 2010, Japanese, 日本音響学会建築音響研究委員会, Kyoto, Domestic conference
    Oral presentation

  • Effect of the honeycomb in the back cavity on the sound absorptivity of panel absorbers: Some considerations on mechanism of absorptivity variation by a honeycomb
    TOYODA Masahiro, SAKAGAMI Kimihiro, MORIMOTO Masayuki, TAKAHASHI Daiji
    2010 Autumn Meeting, Acoustical Society of Japan, Sep. 2010, Japanese, 日本音響学会, Osaka, Domestic conference
    Oral presentation

  • Effect of the honeycomb in the back cavity on the sound absorptivity of panel absorbers: Some considerations on the decrease in absorption coefficient due to a honeycomb
    SAKAGAMI Kimihiro, KONDO Maiko, MORIMOTO Masayuki, TOYODA Masahiro
    2010 Autumn Meeting, Acoustical Society of Japan, Sep. 2010, Japanese, 日本音響学会, Osaka, Domestic conference
    Oral presentation

  • Wideband MPP absorber with a combination of two different perforation MPPs
    YAIRI Motoki, TAKEBAYASHI Kenichi, KOGA Takashi, SAKAGAMI Kimihiro
    2010 Autumn Meeting, Acoustical Society of Japan, Sep. 2010, Japanese, 日本音響学会, Osaka, Domestic conference
    Poster presentation

  • Reduction of sound radiation by using force radiation modes: Effects of attached mass on force radiation modes
    YAMAGUCHI Zenzo, SAKAGAMI Kimihiro, MORIMOTO Masayuki, BOLTON Stuart J, YAMAGIWA Ichiro
    Technical Committee on Architectural Acoustics, Acoustical Society of Japan, Aug. 2010, Japanese, 日本音響学会建築音響研究委員会, Osaka, Domestic conference
    Oral presentation

  • Sound absorption characteristics of a microperforated panel absorber backed by an absorbent layer
    SAKAGAMI Kimihiro, KANO Kenichi, MORIMOTO Masayuki, YAIRI Motoki
    Techinical Committee on Architectural Acoustics, Acoustical Society of Japan, Jun. 2010, Japanese, 日本音響学会建築音響研究委員会, Hiroshima, Domestic conference
    Oral presentation

  • 微細穿孔板吸音構造の吸音特性とその広帯域化
    YAIRI Motoki, SAKAGAMI Kimihiro
    日本音響学会春季研究発表会, Mar. 2010, Japanese, 日本音響学会, 調布市, Domestic conference
    Invited oral presentation

  • 次世代の吸音・遮音技術-最近の研究動向-
    SAKAGAMI Kimihiro
    日本音響学会春季研究発表会, Mar. 2010, Japanese, 日本音響学会, 調布市, Domestic conference
    Invited oral presentation

  • 拡張放射モードによる音響放射パワ低減-質量付加が拡張放射モードに与える影響-
    NAKAHIRA Wataru, SAKAGAMI Kimihiro, MORIMOTO Masayuki, J. Stuart Bolton, YAMAGIWA Ichiro
    日本音響学会春季研究発表会, Mar. 2010, Japanese, 日本音響学会, 調布市, Domestic conference
    Oral presentation

  • 微細穿孔板吸音構造の並列配置による残響室法吸音率の広帯域化-背後壁の振動と周期の影響-
    YAIRI Motoki, TAKEBAYASHI Kenichi, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本音響学会秋季研究発表会, Sep. 2009, Japanese, 日本音響学会, 郡山市, Domestic conference
    Poster presentation

  • 微細穿孔板吸音構造の並列配置による残響室法吸音率の広帯域化-入射面の凹凸の影響-
    TAKEBAYASHI Kenichi, YAIRI Motoki, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本音響学会秋季研究発表会, Sep. 2009, Japanese, 日本音響学会, 郡山市, Domestic conference
    Poster presentation

  • 微細穿孔板(MPP)と通気性膜からなる空間吸音体の吸音特性
    SAKAGAMI Kimihiro, NAKAMORI Tomohito, MORIMOTO Masayuki, YAIRI Motoki
    日本音響学会秋季研究発表会, Sep. 2009, Japanese, 日本音響学会, 郡山市, Domestic conference
    Oral presentation

  • 背後に剛壁を有する2重通気性膜の吸音特性
    FUKUTANI Yusaku, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本音響学会秋季研究発表会, Sep. 2009, Japanese, 日本音響学会, 郡山市, Domestic conference
    Oral presentation

  • 微細穿孔板(MPP)と通気性膜からなる各種吸音構造の吸音特性
    FUKUTANI Yusaku, SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    日本音響学会建築音響研究会, Aug. 2009, Japanese, 日本音響学会建築音響研究委員会, 調布市, Domestic conference
    Oral presentation

  • 2重微細穿孔板(MPP)空間吸音体の吸音特性に対するハニカム構造の影響
    YAMASHITA Ippei, SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    日本音響学会建築音響研究会, Aug. 2009, Japanese, 日本音響学会建築音響研究委員会, 調布市, Domestic conference
    Oral presentation

  • 微細穿孔板吸音構造の並列配置による残響室法吸音率の広帯域化-背後空気層の区画と周期に関する基礎的検討-
    YAIRI Motoki, TAKEBAYASHI Kenichi, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本音響学会建築音響研究会, Jul. 2009, Japanese, 日本音響学会建築音響研究委員会, 長野市, Domestic conference
    Oral presentation

  • 板振動型吸音体の吸音特性に及ぼす背後ハニカム構造の影響
    SAKAGAMI Kimihiro, KONDO Maiko, MORIMOTO Masayuki
    日本音響学会建築音響研究会, Jul. 2009, Japanese, 日本音響学会建築音響研究委員会, 長野市, Domestic conference
    Oral presentation

  • MPPと通気性膜からなる背後に剛壁を有する吸音構造-波動理論による吸音特性の解析-
    FUKUTANI Yusaku, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本建築学会近畿支部研究発表会, Jun. 2009, Japanese, 日本建築学会近畿支部, 大阪市, Domestic conference
    Oral presentation

  • Effect of a honeycomb in a back cavity on the absorption characteristics of an MPP absorber: Detailed analysis based on Helmholtz-Kirchhoff formulation
    SAKAGAMI Kimihiro, YAMASHITA Ippei, MORIMOTO Masayuki, YAIRI Motoki
    日本音響学会建築音響研究会, Mar. 2009, Japanese, 浜松市, Domestic conference
    Oral presentation

  • Analysis of the acoustic properties of a double-leaf permeable membrane
    SAKAGAMI Kimihiro, YOSHIDA Keishi, MORIMOTO Masayuki
    日本音響学会春季研究発表会, Mar. 2009, Japanese, 東京都, Domestic conference
    Oral presentation

  • Effect of a honeycomb in back cavities on the absorption characteristics of an MPP absorber
    YAMASHITA Ippei, SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    日本音響学会秋季研究発表会, Sep. 2008, Japanese, 福岡市, Domestic conference
    Poster presentation

  • A basic study on wideband sound absorbers with a combination of MPP and panel absorbers
    KONDO Maiko, SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    日本音響学会秋季研究発表会, Sep. 2008, Japanese, 福岡市, Domestic conference
    Oral presentation

  • A basic study on wideband sound absorbers with a combination of MPP and porous absorber
    OKAMOTO Naoko, SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    日本音響学会秋季研究発表会, Sep. 2008, Japanese, 福岡市, Domestic conference
    Oral presentation

  • Wideband MPP absorber with a combination of two different depths of the back cavity arranged in parallel
    YAIRI Motoki, TAKEBAYASHI Kenichi, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本音響学会秋季研究発表会, Sep. 2008, Japanese, 福岡市, Domestic conference
    Oral presentation

  • An instruction approach for a graduate thesis project by electro-acoustical equivalent circuit models: Analyses of sound absorbing systems
    SAKAGAMI Kimihiro
    日本音響学会秋季研究発表会, Sep. 2008, Japanese, 福岡市, Domestic conference
    Oral presentation

  • Wideband MPP absorber with a combination of two different depths of the back cavity arranged in parallel
    YAIRI Motoki, TAKEBAYASHI Kenichi, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本音響学会建築音響研究会, Aug. 2008, Japanese, 東京都, Domestic conference
    Oral presentation

  • A basic study on wideband sound absorbers with a combination of MPP and other absorbers
    OKAMOTO Naoko, KONDO Maiko, SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    日本音響学会建築音響研究会, Jul. 2008, Japanese, 吹田市, Domestic conference
    Oral presentation

  • Analysis of sound absorption systems using electro-acoustical equivalent circuit models -An approach for graduate thesis projects-
    SAKAGAMI Kimihiro
    日本音響学会建築音響研究会, Jul. 2008, Japanese, 吹田市, Domestic conference
    Oral presentation

  • A basic study on wideband sound absorbers with a combination of MPP absorber and panel absorber
    KONDO Maiko, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本建築学会近畿支部, Jun. 2008, Japanese, 大阪市, Domestic conference
    Oral presentation

  • A basic study on wideband sound absorbers with a combination of MPP absorber and porous absorber
    OKAMOTO Naoko, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本建築学会近畿支部, Jun. 2008, Japanese, 大阪市, Domestic conference
    Oral presentation

  • Sound absorption of a double-leaf microperforated-panel with an air-back cavity -Detailed discussion with a strict theory-
    MATSUTANI Kiyotaka, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本建築学会近畿支部, Jun. 2008, Japanese, 大阪市, Domestic conference
    Oral presentation

  • A study on sound absorption characteristics of a honeycomb-backed double MPP absorber
    YAMASHITA Ippei, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本建築学会近畿支部, Jun. 2008, Japanese, 大阪市, Domestic conference
    Oral presentation

  • A note on the relationship between the sound absorption by microperforated panels and panel absorbers
    Sakagami, Kimihiro, Morimoto, Masayuki, Yairi, Motoki
    日本音響学会建築音響研究会, Feb. 2008, Japanese, 浜松, Domestic conference
    Oral presentation

  • 二重微細穿孔板空間吸音体に関する実験的検討
    Yairi, Motoki, Sakagami, Kimihiro, Morimoto, Masayuki
    日本音響学会建築音響研究会, Oct. 2007, Japanese, 宮崎, Domestic conference
    Oral presentation

  • A wideband sound absorber with a combination of two microperforated panel absorbers arranged in parallel
    Nagayama, Yoshiki, Sakagami, Kimihiro, Morimoto, Masayuki
    日本音響学会2007年度秋季研究発表会, Sep. 2007, Japanese, 日本音響学会, 甲府, Domestic conference
    Oral presentation

  • 建築材料としての微細穿孔板(MPP)
    Sakagami, Kimihiro
    日本機械学会2007年度年次大会, Sep. 2007, Japanese, 日本機械学会, 吹田, Domestic conference
    Invited oral presentation

  • A basic study on the analysis of the sound field using Fourier series of the boundary condition
    Tanigawa, Masaki, Fukuwaka, Naoko, Sakagami, Kimihiro, Morimoto, Masayuki
    日本音響学会2007年度秋季研究発表会, Sep. 2007, Japanese, 甲府, Domestic conference
    Oral presentation

  • A basic study on wideband sound absorbers with a combination of two MPP absorbers
    Nagayama, Yoshiki, Sakagami, Kimihiro, Morimoto, Masayuki
    Kinki Branch Meeting of Architectural Institute of Japan, Jun. 2007, Japanese, 日本建築学会, Osaka, Domestic conference
    Oral presentation

  • Sound absorption characteristics of a honeycomb-backed microperforated panel (MPP) absorber
    SAKAGAMI Kimihiro, NAKAJIMA Kosuke, MORIMOTO Masayuki, YAIRI Motoki, MINEMURA Atsuo
    4th Joint Meeting of the Acoustical Society of America and the Acoustical Society of Japan, Nov. 2006, English, 米国音響学会, 日本音響学会, Honolulu,Hawai, USA, International conference
    [Invited]
    Invited oral presentation

  • 任意形状の周期構造物周辺の音場解析に関する基礎的考察 その3-観測点位置や音波入射条件等による適用性の変化-
    FUKUWAKA Naoko, TANIGAWA Masanori, MATSUURA Yukiko, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本音響学会秋季研究発表会, Sep. 2006, Japanese, 日本音響学会, 金沢市, Domestic conference
    Oral presentation

  • 3重微細穿孔板(MPP)の吸音特性に関する基礎的研究
    NAKAMORI Tomohito, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本音響学会秋季研究発表会, Sep. 2006, Japanese, 日本音響学会, 金沢市, Domestic conference
    Oral presentation

  • 微細穿孔板(MPP)の建築内装への適用について -補強のための2,3の試みとその音響的影響-
    SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki, MINEMURA Atsuo
    日本音響学会 建築音響研究会, Jun. 2006, Japanese, 日本音響学会 建築音響研究会, 国分寺市, Domestic conference
    Oral presentation

  • 周期構造物周辺の音場解析に関する基礎的研究―周期境界条件を考慮した解析法の適用範囲―
    FUKUWAKA Naoko, TANIGAWA Masanori, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本建築学会近畿支部研究発表会, Jun. 2006, Japanese, 日本建築学会近畿支部, 大阪市, Domestic conference
    Oral presentation

  • 3重微細穿孔板の吸音特性に関する基礎的研究
    NAKAMORI Tomohito, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    日本建築学会近畿支部研究発表会, Jun. 2006, Japanese, 日本建築学会近畿支部, 大阪市, Domestic conference
    Oral presentation

  • Effect of honeycomb structure in the back cavity on the absorption characteristics of microperforated panel absorbers: 2.Attempt of model analysis
    SAKAGAMI Kimihiro, NAKAJIMA Kosuke, MORIMOTO Masayuki, YAIRI Motoki, MINEMURA Atsuo
    2006 Spring Meeting, Acoustical Society of Japan, Mar. 2006, Japanese, 日本音響学会, Nihon University, Domestic conference
    Oral presentation

  • Effect of honeycomb structure in the back cavity on the absorption characteristics of microperforated panel absorbers: 1.Experimental considerations
    YAIRI Motoki, SAKAGAMI Kimihiro, MORIMOTO Masayuki, TOYODA Emi, SUGIE Satoshi, MINEMURA ATSUO
    2006 Spring Meeting, Acoustical Society of Japan, Mar. 2006, Japanese, 日本音響学会, Nihon University, Domestic conference
    Oral presentation

  • *Acoustical properties of microperforated panel absorbers with various back cavity configurations
    YAIRI Motoki, SAKAGAMI Kimihiro, MORIMOTO Masayuki, MINEMURA Atsuo
    2005 Autumn Meeting, Acoustical Society of Japan, Sep. 2005, Japanese, 日本音響学会, Tohoku University, Domestic conference
    Oral presentation

  • The effect of back honeycomb structure on sound absorption characteristics of microperforated panel absorber
    NAKAJIMA Kosuke, SAKAGAMI Kimihiro, MORIMOTO Masayuki, YAIRI Motoki
    Technical Committee on Architectural Acoustics, Acoustical Society of Japan, Jul. 2005, Japanese, 日本音響学会, Kobe University, Domestic conference
    Oral presentation

  • A basic study on the analysis of sound fields around periodic structures - Boundary integral equation analysis using the Green funcion for a periodic boundary condition-
    MATSUURA Yukiko, TANIGAWA Masaki, SAKAGAMI Kimihiro, MORIMOTO Masayuki
    Kinki Branch, Architectural Institute of Japan, Jun. 2005, Japanese, 日本建築学会, 大阪科学技術専門学校, Domestic conference
    Oral presentation

  • A basic study on the sound field analysis of periodic structures by boundary integral equation
    TANIGAWA Masaki, SAKAGAMI Kimihiro, MORIMOTO Masayuki, MATSUURA Yukiko
    Technical Committee on Architectural Acoustics, Acoustical Society of Japan, Apr. 2005, Japanese, 日本音響学会, Hiroshima International University, Domestic conference
    Oral presentation

  • 任意形状の周辺構造物の音場解析に関する基礎的考察をの2-有限個構造物周辺の音場環境への適用
    谷川 将規, 阪上 公博, 森本 政之
    日本音響学会 春季研究発表会, 2004, Japanese, 日本音響学会, 琉球大学, Domestic conference
    Oral presentation

  • 任意形状の周期構造物周辺の音場解析に関する基礎的考察- 周期境界条件を満たすGreen関数を用いた境界積分方程式法-
    谷川 将規, 阪上 公博, 森本 政之
    日本音響学会 秋季研究発表会, 2004, Japanese, 日本音響学会, 琉球大学, Domestic conference
    Oral presentation

  • 2重微小穿板と背後壁からなる吸音構造の吸音特性に関する研究-背後構造の影響-
    中島 幸祐, 阪上 公博, 森本 政之
    日本建築学会近畿支部研究発表会, 2004, Japanese, 日本建築学会近畿支部, 大阪工業技術専門学校, Domestic conference
    Oral presentation

  • 2重Microperforated panelの吸音特性に関する基礎的考察
    阪上 公博, 小池 若菜, 森本 政之
    日本音響学会音響研究会, 2004, Japanese, 日本音響学会音響研究会, 未記入, Domestic conference
    Oral presentation

  • 橋梁高架構造物音の計算方法についての一考察
    紺野 義仁, 池谷 公一, 阪上 公博, 鳥海 英宏, 山本 貢平
    日本音響学会騒音・振動研究会, Mar. 2003, Japanese, 日本音響学会 騒音・振動研究委員会, 日本自動車研究所, Domestic conference
    Others

  • 多孔質型吸音材の吸音特性に対する表面保護フィルムの影響
    西尾 純子, 阪上 公博, 森本 政之
    日本建築学会近畿支部2003年度研究報告会, 2003, Japanese, 日本建築学会近畿支部, 未記入, Domestic conference
    Oral presentation

  • 多孔質吸音材の吸音特性に対する表面保護フィルムの影響
    阪上 公博, 西尾 純子, 森本 政之
    日本音響学会2003年秋期研究発表会, 2003, Japanese, 日本音響学会, 大同工業大学, Domestic conference
    Oral presentation

  • 2重通気性膜構造の吸音特性に関する基礎的研究
    江山 真衣, 阪上 公博, 森本 政之
    日本建築学会近畿支部2003年度研究報告会, 2003, Japanese, 日本建築学会近畿支部, 未記入, Domestic conference
    Oral presentation

■ Affiliated Academic Society
  • Institute of International Sound and Vibration

  • 米国音響学会

  • 日本騒音制御工学会

  • 日本建築学会

  • 日本音響学会

■ Research Themes
  • Challenges in improvement of acoustic environment in buildings in 'new lifestyle'
    阪上 公博
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2021 - 31 Mar. 2024
    新生活様式における建築音環境改善手法として,本年度は(1)MPPを使用した吸音性を持つ透明アクリル製卓上パーティションの,室内実装時の効果についての実験的検討,(2)自然換気機能を持つプレナムドアの遮音効果に関する実験的基礎検討を実施した. (2)は当初の計画にはなかったが,その課題としての重要性から急遽,本年度の計画に入れて検討したものである. (1)については,本課題開始前の準備的検討において試作実験によって仕様策定したパーティションを試作し,(A)残響時間の短い響きの少ない室,および(B)残響時間が長く響きの多い室の2つにおいて,パーティションを実際に設置し,MPPの有無によってどの程度の室内音響指標が変化するか,実際の使用状況を想定して,実験的に室内音響指標を測定して検討した.その結果,(B)においては,音声明瞭度に関する指標を中心に,吸音効果による若干の音響的改善が見られたが,(A)においては明確かつ顕著な効果は見られなかった.もともと残響の少ない室においては,吸音の効果は表れにくいが,今回はパーティションの面積が小さいこと及び使用したMPPの仕様について改善が必要であることが考えられた.これについては,次年度以降の課題として検討したいと考えている. (2)については,一般的な連続する2つのオフィスの開口部に,プレナムドアを設置し,室間音圧レベルを測定して遮音効果を実験的に検討した.その結果,プレナム内部に吸音処理をした場合は高周波数域において最大20dB程度,吸音処理がない場合でも低周波数域5dB程度,高周波数域で13dB程度の遮音効果を得ることができた.今後は,数値解析等を併用して,より効果的な仕様を策定できるよう検討する予定である.

  • 阪上 公博
    科学研究費補助金/基盤研究(C), 2008, Principal investigator
    Competitive research funding

  • A Study on the Generating Mechanism of Elevated Structure Noise and Its Countermeasures
    MORIMOTO Masayuki, SAKAGAMI Kimihiro, KITAMURA Yasutoshi
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for General Scientific Research (B), Grant-in-Aid for General Scientific Research (B), Kobe University, 1994 - 1995
    The problems with the elevated structure noise, which is the noise in audio-frequency range radiated from the structural elements of the elevated motorway, recently arises around the elevated motorways. To investigate the mechanism of the generation of, and to establish the countermeasure to the elevated structure noise, the following considerations were carried out : 1. Model analysis of the acoustic radiation of steel I-beams : The sound radiation characteristics of web plate of steel I-beams were analyzed using a simplified model. The beam was modelled a baffled strip of elastic plate of infinite length in the model analysis. The features of the calculated results were discussed in comparison with those of those of the actual elevated structure noise in order to shed some light on the main cause of the noise. 2. Boundary element analysis of the vibration of steel I-beams : To make a further investigation on the main cause of the noise, vibration of a steel I-beam was analyzed by boundary element method (BEM). The relationship between the elevated structure noise and the structure of the beam was discussed in detail from the above BEM results. As the results from the model analysis, the radiated sound from an elastic plate strip of infinite length was found to have very similar features to the elevated structure noise. This can be interpreted to imply that steel I-beams can possibly be the main cause of the elevated structure noise. The results of the BEM analysis show that the transverse vibration, which may be the most responsible to sound radiation, is dominant in the web plate around 500Hz, and it is still dominant when the web is excited by a nearly in-plane force. These results suggest that the web plate of steel I-beams is strongly relevant to the elevated structure noise. From the above results, it can be concluded that the main cause of the elevated structure noise is the web plate of steel I-beams. Though there is still some problems to be solved, which include the actual excitation condition of the beam, for example, the above results can help with basic ideas for countermeasures to the elevated structure noise problems.

  • オ-ディトリアムにおけるステージ床の音響特性に関する基礎的研究
    阪上 公博
    日本学術振興会, 科学研究費助成事業 奨励研究(A), 奨励研究(A), 神戸大学, 1994 - 1994
    本年度の研究においては、オ-ディトリアムにおける舞台床の音響特性について考察する上で重要な、次の2つの問題について、理論解析によって究明を試みた. (1)球面波入射に対する無限大弾性板の音響反射特性 (2)球面波入射及び点加振力を受ける無限大弾性板の音響特性 上記(1)は、舞台床が音源に極めて近接していること、(2)は、チェロやコントラバスのように床と音源(楽器)が接触していることを、条件として考慮したものである。なお、実際の建築条件においてしばしば見られる床下の空気層あるいは奈落のスペースについて、それらの影響を考慮するため、(1)、(2)ともに板が背後空気層を有する場合についても解析を行ない、考察した. その結果、(1)については遠距離受音点での近似解が、平面波入射の場合の解とほとんど同形であり、同様の性質を有することが示された.(2)については、(1)の解と、点加振力による放射音圧の和となり、両者のエネルギ和を中心として、干渉によって変動することを示した.いずれの場合においても、背後空気層の影響は、著しいディップとして現れる. なお、(2)については、音源と加振力の位相関係の影響が大きく、低音域に著しい反射性の増加あるいは減少を生じる.この点について、実際の楽器における加振力特性を実測調査しているが、未だ十分な知見は得られていない.

  • オ-ディトリアムにおける音響反射板の設計に関する研究
    阪上 公博
    日本学術振興会, 科学研究費助成事業 奨励研究(A), 奨励研究(A), 神戸大学, 1993 - 1993
    本研究では,オ-ディトリアムにおける音響反射板の設計指針を得るため,これまで全く解かれていない,背後構造を持つ無限大弾性板の音響反射問題を,平面波入射の場合について理論的に解き,以下の知見を得た. 1.背後空気層・吸音層を有する板の反射・吸音問題について,本研究で得た理論解が,実測値と良好に一致することを確認した.理論解析結果から,背後層を持つ板の反射特性は,低周波数域に顕著なディップを持つことを示し,反射面として使用する場合には注意を要することを指摘した.また,板の諸定数や背後層厚,構成,層内の媒質によって,反射・吸音特性がどのように変化するかを明らかにした. 2.背後層とリブ(野縁)を有する板の場合,リブの効果によって低音域で反射率が上昇し,中高域に多くのディップを生じることが分かった.したがって,しばしば問題となる低音域での反射性を向上するには,リブが若干の効果を持つことを示した.また,反射特性に及ぼすパラメタの影響を明らかにした. 上記に加え,球面波が入射する場合の単一の無限大弾性板による反射音場を解析し,平面波入射に対する結果との比較により,音波の入射条件の違いによる影響について考察した.その結果,板の物性値等による影響は,平面波入射の場合と同様であることを示した. また,関連する問題として,膜による音響反射問題についても理論的に解析し,薄く軽い膜でも,条件によっては反射板として利用可能であることを示した.また,反射板の材質を選択するための指標として,単一の無限大弾性板の反射率が低音域で0.5まで低下する周波数をカットオフ周波数と定義し,理論解を示すとともに計算図表を提案した.

■ Industrial Property Rights
  • 微細穿孔板利用の吸音構造及び吸音材
    SAKAGAMI KIMIHIRO
    特願2005-192339, 30 Jun. 2005, 大学長, 特許5008277, 08 Jun. 2012
    Patent right

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