藤谷 秀雄 | ![]() |
フジタニ ヒデオ | |
大学院工学研究科 建築学専攻 | |
教授 | |
土木・建築工学関係 |
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研究論文(学術雑誌)
© Copyright © 2020 Mukai, Yokoyama, Fushihara, Fujinaga and Fujitani. The seismic responses of a single-story reinforced concrete (RC) frame building model under control using an active mass damper (AMD) are demonstrated through a real-time hybrid simulation (RTHS) method. In this study, the RTHS test is carried out by using a hydraulic actuator and a shaking table under synchronization. Most parts of the target RC frame model are provided as an analytical model for an online computer simulation, and only the single column of the first story is prepared as an experimental substructure. A hydraulic actuator deforms the actual RC column, and uncertainty or nonlinearity of the RC column’s behavior is focused on in this RTHS test. At the same time, a control device of AMD is actually tested under a situation of installing it on the target building’s floor. The floor response of the target building model is generated using a shaking table. A control motion of the AMD is manipulated based on an online simulation of the entire RC building model. Firstly, a time delay compensation of the hydraulic actuator is considered. Time delay parameters are identified using a combination model of a time lag and a first-order delay. A PID controller and a time series compensator are applied to improve actuator performances. Next, the reproducibility of the RTHS test using two-individual actuators is evaluated. The tracking of a restoring force and deformation of the actual RC column specimen generated by the hydraulic actuator and floor motion responses reproduced on the shaking table are investigated. To improve the online numerical simulation based on the measured force responses of the RC column specimen, a high-pass filter (HPF) is applied for a force correction to utilize its phase-lead property. The effect of this HPF force correction is evaluated in both a linear region and a strong nonlinear region of the actual RC column specimen. Finally, the RTHS test results are compared to fully numerical simulations and the control effect of the AMD to increase the damping effect for the target RC building model is also investigated.
Frontiers Media SA, 2020年11月04日, Frontiers in Built Environment, 6研究論文(学術雑誌)
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This paper proposes a new damper that can change the damping force depending on the response displacement and response velocity. The proposed damper reduces the damage of seismic-isolated structures which undergo excessive deformation during huge earthquakes, without lowering the performance of the seismic-isolation system during medium to small magnitude earthquakes. We investigate the effects of using the proposed attenuator on the responses of a superstructure model to seismic motion that causes collision with retaining walls. An experiment using a shaking table is conducted, and the results from the test are compared with those from numerical analyses. The test results agree approximately with the numerical analysis results except for the absolute acceleration results in collision cases.
SPIE-INT SOC OPTICAL ENGINEERING, 2017年, SENSORS AND SMART STRUCTURES TECHNOLOGIES FOR CIVIL, MECHANICAL, AND AEROSPACE SYSTEMS 2017, 10168, 10168 - 33, 英語[査読有り]
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Authors propoo real tune hybrid tt method using shaking table br emitiw control. 'Ibis test iiystem uses test qxctmen and a semiactivo damper on the shaking tabk and the lumped mass model in a computer. It is possible to apply fbr an experiment supposing midstrny isolated building. In this semi-active conthil, rotary inertia mass daniper encapsulating magnetorheological fluid is used. Send-active control can't avoid a control time lag. This time lag Ic also estimated by acsuming the firiconler delay system. Authors compare experimental results with analytical results considering a control time lag in this papeI The validity o(thii, IVal tinS' hybrid test is verified.
Architectural Institute of Japan, 2016年11月01日, Journal of Structural and Construction Engineering, 81 (729), 1821 - 1829, 英語[査読有り]
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An earthquake with a magnitude of 7.8 (Mw) occurred at 11:56 NST (local time) on 25 April 2015, in the central part of Nepal (Gorkha).We organized a damage survey team and dispatched it to the affected area for several periods following the earthquake (May 26 to June 3: first trip, June 17 to 24: second trip, August 16 to 21: third trip and October 27 to November 2: forth trip) to investigate the damage and collect data. We found traditional construction methods are stronger than imagined. Many traditional earthquake-resistance technologies exist in Nepal. The first and second surveys were to collect timely statistical information on the damage to brick and stone masonry buildings and to confirm the availability of data and their sources for subsequent surveys. We also carried out a first-hand building damage survey in selected areas. The investigation of the strong-motion data set from the USGS Center for Engineering Strong Motion Data includes information from stations in Nepal that continued to function throughout the main shock and the several subsequent strong aftershocks of the 2015 earthquake. The third and fourth surveys were to collect the every building damage survey in selected areas. The motivation behind the survey was to obtain ground truth data for the calibration and improvement of a wide-area damage estimation system that uses satellite data the system is currently under development by National Research Institute for Earth Science and Disaster Prevention (NEID) and the Japan Aerospace Exploration Agency (JAXA). A survey of the degree of damage was conducted for every house in Sankhu and Khokana by the European Macroseismic Scale (EMS) -98. This report outlines the findings of this investigation team into various aspects of the earthquake disaster in the Kathmandu Valley. The motivation behind the survey was to obtain ground truth data for the calibration and improvement of a wide-area damage estimation system that uses satellite data. Field surveys confirmed that the severely damaged urban area was well detected by the decrease derived from the ALOS-2 satellite SAR data. The higher classification accuracy for non-damaged area helps to detect the damaged urban area using this technique, immediately after a disaster.
Springer International Publishing, 2016年08月01日, Geotechnical and Geological Engineering, 34 (4), 1223 - 1245, 英語[査読有り]
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The dynamic characteristics of mid-story isolated buildings and seismic response reduction due to a semi-active control system were investigated using a three-lumped-mass model that simplified the sixteen story building with an isolation layer in the sixth story. A semi-active control method using a rotary inertia mass damper filled with magnetorheological fluid (MR fluid) was proposed. The damper shows both mass amplification effect due to rotational inertia and variable damping effect due to the MR fluid. The damping force is controlled by the strength of the magnetic field that is applied to the MR fluid. It is determined by using the electric current, which is calculated by the proposed semi-active control method based on the velocity of the isolation layer relative to the layer just underneath it. Real-time hybrid tests using an actual damper and simulations using a building model were conducted to check the damper model; the test results were in good agreement with the simulation results. The simulation results suggest that the response displacement of the structure above the isolation layer is significantly reduced, without increasing the response acceleration of the entire structure against near-fault pulse and long-period ground motions. The proposed semi-active control using an MR rotary inertia mass damper was confirmed to be effective for mid-story isolated buildings.
SPIE-INT SOC OPTICAL ENGINEERING, 2015年, ACTIVE AND PASSIVE SMART STRUCTURES AND INTEGRATED SYSTEMS 2015, 9431, 英語[査読有り]
研究論文(国際会議プロシーディングス)
In this paper, through the real-time-hybrid experiment with the use of "MR rotary inertia damper" the authors have been developed, the seismic response properties are discussed by changes in the parameters on building structure. The setup parameters in this paper are three of the followings natural period of building structure, inertia mass ratio to building structure mass and variety of input earthquake motion. From the knowledge obtained by the experiment, the authors propose the semi-active control method focused on input velocity of earthquake. Then, in comparison between passive control and semi-active control, it have been confirmed the effects of the displacement reduction in the all case of experiments performed in this paper. Especially, in the case of JMAKobe earthquake, by the proposed semi-active control, it have been confirmed both floor response acceleration and displacement were reduced.
日本建築学会, 2014年10月01日, 日本建築学会構造系論文集, 79 (704), 1435 - 1444, 日本語[査読有り]
研究論文(学術雑誌)
This paper shows a response control efficacy by using rotational inertia mass damper filled with magnetorheological fluid. Through a study on transfer function of the frequency domain, authors indicate the effective range of decreasing floor response acceleration by designing proper mass ratio. But, on passive control, they have the performance tradeoff between mass ratio and damping ratio, and there is a limit to decrease both floor response acceleration and response displacement. Then, authors suggest the skyhook-type semi-active control method. The suggested method makes it possible to decrease response on sympathetic vibration point and not to worsen response in high frequency range. Next, through a study on time history response, authors shows the skyhook-type semi-active control is effective to decrease both floor response acceleration and response displacement.
日本建築学会, 2014年09月01日, 日本建築学会構造系論文集, 79 (703), 1237 - 1246, 日本語[査読有り]
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This study elucidates a method to ascertain control variables such as the performance function and weight coefficient, at the initial stage of structural design. For the purpose, authors assess the structural properties (equivalent damping factor and equivalent natural circular frequency) of semi-active optimal control system by MR damper to evaluate the structure response. First, the relations between weight coefficient and those system properties are discussed. Secondly, control parameter determination in consideration in the maximum controlling force is proposed. Validity of those design proposals are investigated by real-time hybrid experiments and numerical simulations.
2013年07月, Journal of Structural and Construction Engineering, 78 (689), 1237 - 1245, 日本語[査読有り]
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MRダンパーを用いたセミアクティブ最適制御を対象として,制御パラメータと制御効果との直接的関係について述べた。
日本建築学会, 2013年07月, 日本建築学会構造系論文集, 78 (689), 1237 - 1245, 日本語[査読有り]
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The authors have developed a new aseismic device, which has a ball screw and rotational mass. It not only generates the resistive inertial force originating in the rotational mass but also dissipates the energy of vibration through a viscous damping mechanism. Furthermore, the damping capability of the device can be controlled externally with an applied magnetic field. A magneto-rheological (MR) fluid is used to change the dynamic characteristics of the device. Through comprehensive experimental testing of a prototype device, the dynamic characteristics of the device have been verified. The test results show that the force-displacement relationship varies with an applied magnetic condition. Only a few amperes of electric current is required to generate a magnetic field effective for the prototype device with a capacity of 100kN. Copyright © 2013 by ASME.
2013年, American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP, 8, 英語[査読有り]
研究論文(国際会議プロシーディングス)
This paper shows fundamental properties of the damper authors have been developed with the aim of vibration control of building structures. The damper developed by authors uses both the mass effect by rotary inertia and the variable damping effect by magnetorheological fluid. In this paper, authors make a 100kN type test model of the damper developed, and experiment to bring out its performances with vibration tests by sine wave input, etc. In sine wave tests, the negative spring property by inertia mass and significant energy absorption by MR fluid are confirmed. Authors also confirm the validity of theories and analytical method on knowledge from performance test. And authors intend to carry out practical realization of rotary inertia mass damper using MR fluid.
Architectural Institute of Japan, 2013年, 日本建築学会構造系論文集, 78 (693), 1859 - 1867, 日本語[査読有り]
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In the base isolation system, when the response is controlled, it is said that the semi-active control by the variable damper is effective, because it can decrease the response displacement without raising the absolute acceleration. Authors use Magneto-rheological fluid damper (MR damper) for the semi-active control, and conducted the real time hybrid test that considers the uncertainty of modeling of the MR damper. The results of the real time hybrid test are compared with those of shaking table test and analytical simulation. Thus, the effectiveness of the evaluation of the semi-active control in the base isolation system by the real time hybrid test is verified. In this study, the optimum control theory is used for control techniques.
2011年05月, Journal of Structural and Construction Engineering, 76 (663), 891 - 897, 日本語[査読有り]
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A two-story, two-span by two-bay frame was set up on E-Defense shaking table, and curtain walls made of metal sashes and glasses were attached with typical connection details. In a series of tests, seismic responses of a high-rise building were reproduced in the frame. First, damage of the curtain walls in expected seismic responses (the maximum inter-story drift angle is 0.02 rad) was observed. The possibility that the curtain walls come off and drop from the frame was also considered in an ultimate deformation range (the maximum interstory drift angle is 0.04 rad).
2010年06月, AIJ Journal of Technology and Design, 16 (33), 535 - 540, 日本語[査読有り]
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In the last years there has been an increasing interest to magnetorheological (MR) dampers and their applications to civil engineering. In particular they have been used as semi-active control devices for vibration mitigation due to external dynamic loads. These devices are highly nonlinear and thus applicable models of these devices are important for effective simulation and control system design. Two hysteretic models based on the normalized Bouc-Wen model are used in this paper to compare their effectiveness in a long-stroke MR fluid damper. A methodology for identification is proposed, and the obtained models are tested and validated experimentally.
一般社団法人日本建築学会, 2010年03月, 構造工学論文集, 56B, 127 - 136, 英語[査読有り]
A two-story, two-span by two-bay frame was set up on E-Defense shaking table, and exterior walls made of ALC panels were attached to the frame with typical connection details. In a series of tests, seismic responses of a high-rise building were reproduced in the frame. First, damage of ALC panels in expected seismic responses (the maximum inter-story drift angle is 0.02 rad) was observed. The possibility that the ALC panels come off and drop from the frame was also considered in an ultimate deformation range (the maximum inter-story drift angle is 0.04 rad).
2009年10月, AIJ Journal of Technology and Design, 15 (31), 667 - 672, 日本語[査読有り]
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Magnetorheological damper (MR damper) has been expected to control the response of civil and building structures in recent years, because of its large force capacity and variable force characteristics. In this paper, a series of real-time hybrid test was conducted and the results of real time hybrid tests were compared to those of shaking table tests. To determine the control force of the MR damper, skyhook control and sliding mode control theory were employed. As the results, the validity of real-time hybrid test was verified. This paper describes the capability of MR damper to control the structural response.
TRANS TECH PUBLICATIONS LTD, 2009年, EMBODING INTELLIGENCE IN STRUCTURES AND INTEGRATED SYSTEMS, 56, 212 - +, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Recently, the semi-active control method has attracted significant attention from many researchers and engineers. This method aims to minimize a structure's response by changing the damper capacity according to the state of the structure and the external loads, and various kinds of semi-active control algorithms have been proposed. A lot of them utilize mathematically difficult algorithms that require complicated computer systems. With these methods, we can not evaluate the effectiveness and overall safety of the system under various kinds of loads. One reason is that the behaviors of structures incorporating such complicated control systems can not be evaluated by conventional means such as equivalent viscous damping factor based on hysteresis. Therefore, a semi-active control system is wished in which the control effects can be easily quantified as with passive control systems. This paper describes the result of having proposed the simple quantification approach for the semi-active control effectiveness.
TRANS TECH PUBLICATIONS LTD, 2009年, EMBODING INTELLIGENCE IN STRUCTURES AND INTEGRATED SYSTEMS, 56, 265 - +, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Magnetorheological damper (MR damper) has been expected to control the response of civil and building structures in recent years, because of its large force capacity and variable force characteristics. In this paper, a series of real-time hybrid test was conducted and the results of real time hybrid tests were compared to those of shaking table tests. To determine the control force of the MR damper, skyhook control and sliding mode control theory were employed. As the results, the validity of real-time hybrid test was verified. This paper describes the capability of MR damper to control the structural response.
TRANS TECH PUBLICATIONS LTD, 2009年, EMBODING INTELLIGENCE IN STRUCTURES AND INTEGRATED SYSTEMS, 56, 212 - +, 英語[査読有り]
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Recently, the semi-active control method has attracted significant attention from many researchers and engineers. This method aims to minimize a structure's response by changing the damper capacity according to the state of the structure and the external loads, and various kinds of semi-active control algorithms have been proposed. A lot of them utilize mathematically difficult algorithms that require complicated computer systems. With these methods, we can not evaluate the effectiveness and overall safety of the system under various kinds of loads. One reason is that the behaviors of structures incorporating such complicated control systems can not be evaluated by conventional means such as equivalent viscous damping factor based on hysteresis. Therefore, a semi-active control system is wished in which the control effects can be easily quantified as with passive control systems. This paper describes the result of having proposed the simple quantification approach for the semi-active control effectiveness.
2008年07月, Journal of Structural and Construction Engineering, 73 (629), 1071 - 1077, 日本語[査読有り]
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abs Furniture and nonstructural components in high-rise buildings are subjected to intense seismic responses. To obtain physical data on their seismic behaviors, shaking table tests are conducted. A two-story frame is built on a concrete slab supported by rubberisolators. Cladding walls are fastened in the exterior frames. Furniture is placed on thesectioned floor. the design process of the test system is presented, and its vibration characteristics are considered. preliminary sismic response analyses for a generic thirty-story building are conducted and referred to. Designed waves are input into the shaking table to produce the equivalent floor responses in the test systme.
2008年06月, Journal of Structural and Construction Engineering, 73 (628), 1007 - 1014, 日本語[査読有り]
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Structural vibration control is categorized into passive control, active control and semi-active control. Semi-active control using a variable damper stabilizes building responses in an earthquake better than the conventional passive control and active control. This paper used variable hydraulic damper and MR damper. The servo valve of variable hydraulic damper controls the oil flow between two rooms of the cylinder divided by the piston. MR damper changes its damping force by changing the magnetic field acting on the MR fluid according to an electric current. As the first step of the research, in order to evaluate the performance expected from the theoretical study, a dynamic loading test was conducted. Next, authors conducted experiment by the base-isolated specimen of two-degree-of-freedom structure. Finally, the damping performance and control characteristics of semi-active damper were verified.
2008年04月, Journal of Structural and Construction Engineering, 73 (626), 519 - 525, 日本語[査読有り]
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Magnetorheological fluid damper (MR damper) has been expected to control the response of civil and building structures in recent years, because of its large force capacity and variable force characteristics. At first, a series of real-time hybrid tests was conducted. The important objective of this paper is to verify the validity of real-time hybrid tests by comparison with the test results of shaking table tests by using the same MR damper. The maximum damping force of the MR damper is 10 (kN), the stroke is 600(p-p) (mm), and the maximum piston velocity is 1(m/s). To determine the control force of the W damper, optimal control theory and skyhook control were employed. The capability of the MR damper to control the response displacements and accelerations of base isolation system was verified by both shaking table tests and real-time hybrid tests.
SPIE-INT SOC OPTICAL ENGINEERING, 2008年, SENSORS AND SMART STRUCTURES TECHNOLOGIES FOR CIVIL, MECHANICAL, AND AEROSPACE SYSTEMS 2008, PTS 1 AND 2, 6932, 英語[査読有り]
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Semi-active vibration control has attracted a great deal of attention taking advantage of vibration reduction effect, control stability and effective energy consumption. An MR damper is known as one of semi-active control devices. In this paper, experiments for seismic response reduction were conducted on a full-scale building structural model equipped with an MR damper. It is difficult to deal with time variation of properties of the MR damper and nonlinearity of the structure. It is another problem that optimal damping may be varied according to shape and magnitude of a wave inputted to the structure. In order to deal with these problems, neural networks were applied to the vibration control system. As a result of the experiments, it is shown that the displacement of each floor of the structure was reduced by neural network control system as much as optimal damping, simultaneously with suppressing the acceleration to some extent.
一般社団法人日本建築学会, 2006年03月, 構造工学論文集, Vol.52B, pp.261-266, 261 - 266, 日本語[査読有り]
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This article proposes a new framework for performance-based design (PBD) of building structures. This framework was proposed under the 3-year Japanese Government Comprehensive Research and Development Project on "Development of a New Engineering Framework for Building Structures" launched in the fiscal year of 1995. The primary objective of the project is to create a system in which the performance of buildings is clearly stated, and consumers, that is, occupants, are well informed of how their buildings will perform and how much it will cost to maintain their performance. The framework emphasizes the establishment of target performance, the performance evaluation, and the performance statement as the main three elements. It also stresses that an institutional framework and support systems need to be provided to enable PBD to be practiced efficiently. The implementation of the proposed framework is also expected to promote engineering innovation, progress in building engineering, and globalization. The new framework will also bring other benefits, such as improved design techniques, greater design flexibility, and international harmonization. It is also important for building structural performance to become one of the most important indexes for consumers to define a building's value. The Japanese building code was changed to the performance-based code, based in the clear and comprehensive manner proposed in this article. In the United States, "Vision 2000" (SEAOC, 1995) was published, then many research activities were conducted simultaneously.
BLACKWELL PUBLISHERS, 2005年01月, COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, 20 (1), 62 - 77, 英語[査読有り]
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研究論文(学術雑誌)
This study deals with a shake table test on a three-story base-isolated steel frame. The frame rests on four roller bearings for isolation and is equipped with four laminated rubbers as shear spring. An MR damper is used in the test to perform semi-active seismic response control. The basic control algorithm applied in the study is to simulate the load-deflection relation of an origin-restoring friction damper (ORFD) which is a sort of friction damper that looses its resistance when it moves toward the origin, making sure for the base-isolated system to minimize residual displacement even after an extremely strong ground motion. Also attempted is a hybrid type control that superposes viscous damping on the ORFD when the damper moves from the peak displacement toward the origin.
2003年, Proceedings of SPIE - The International Society for Optical Engineering, 5052, 460 - 467, 英語[査読有り]
研究論文(国際会議プロシーディングス)
A 400kN magnetorheological damper (MR damper) for a real base-isolated building was developed and its dynamic characteristics were verified by experimental tests. The MR damper has 950mm (+/-475mm) stroke and by-pass flow potion. A new type of Magnetorheological fluid is also developed in order to apply to the MR damper. MR fluid had a property of the settlement of particles in dampers. Authors developed a new MR fluid, which keeps the particles in the fluid adequately enough for usual use of MR damper. Analytical model was discussed in this paper. The force by the bingham visco-plastic model was compared with the results of experimental tests. It was found that this analytical model is useful to predict the capacity of the MR damper.
2003年, Proceedings of SPIE - The International Society for Optical Engineering, 5052, 265 - 276, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Recent study is to the performance of variable dampers for reducing earthquake response of buildings or wind induced sway. The variable damper using magnetorheological fluid (MR damper) changes its damping force by changing the magnetic field acting on the MR fluid according to an electric current. MR dampers have a simple mechanism and don't need a large amount of energy. Semi-active control using such a variable damper stabilizes building responses in an earthquake better than the conventional passive control. Basic characteristics of the MR damper have been clarified.This time, authors proposed control algorithm of base-isolated structure, which carried out semi-active control by optimal regulator theory. This control algorithm reduces response displacement and response acceleration for the purpose of, and aims at enhancements, such as safety and amenity. This paper presents a comprehensive study on the performance of the MR damper to base-isolated structure. It's describes shaking table tests on a three-story large-scale test frame with base-isolated structure. The test results verify the controlling system and the control effect as a semi-active device of the MR damper.
2003年, Proceedings of SPIE - The International Society for Optical Engineering, 5056, 400 - 411, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Magneto-rheological fluid dampers (MR dampers) have recently been designed to control the response of civil engineering and building structures because of their large force capacity and controllable force characteristics. To enable them to control structural responses, the dynamic characteristics of structures need to be clarified. This paper discusses the design of MR dampers with a bypass orifice mechanism and verifies their performance by means of dynamic tests and dynamic analytical models. Their dynamic characteristics are investigated experimentally to compare the performance of two different magneto-rheological fluids. One is developed by the Lord Corporation and the other is newly developed in Japan. The effectiveness and validity of MR dampers with a bypass are discussed on the basis of these results.
Blackwell Publishing Inc., 2003年, Computer-Aided Civil and Infrastructure Engineering, 18 (1), 45 - 57, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(研究会,シンポジウム資料等)
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研究論文(研究会,シンポジウム資料等)
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研究論文(研究会,シンポジウム資料等)
A building inventory is important not only for building damage estimation due to earthquakes, but also for earthquake disaster management planning. "The study on earthquake disaster mitigation in the Kathmandu Valley JICA, 2002)" was conducted to evaluate building vulnerability to strong earthquakes. However, until then, only partial databases on the existing buildings in the Valley have been prepared. A questionnaire format was newly developed. 69 sample areas were selected by the stratification multistage extraction method, and 1,183 buildings (0.4% of the Valley) were surveyed. Their results provided the outline of natures and characteristics in the Valley, and then, they were utilized to the damage assessment as well as the earthquake disaster management planning.
地域安全学会, 2002年11月, 地域安全学会論文集, 4 (4), 175 - 182, 日本語[査読有り]
研究論文(学術雑誌)
During "The study on earthquake disaster mitigation in the Kathmandu Valley (JICA, 2002)", in order to establish the disaster mitigation plan, hazard and damage analysis were conducted. The building damage due to both the three scenario earthquakes and the 1934 earthquake were estimated. In the analyses, building inventory database, vulnerability function for each structural type were developed. The results provided the actual image of miserable disasters and necessity of measures against them. Then, several proposals for improvement of the earthquake-resisting capacity in the Kathmandu Valley were issued.
地域安全学会, 2002年11月, 地域安全学会論文集, 4 (4), 183 - 190, 日本語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
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研究論文(国際会議プロシーディングス)
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研究論文(国際会議プロシーディングス)
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研究論文(国際会議プロシーディングス)
This paper presents a comprehensive study on the application of the MR damper to base-isolated building structures. It first proposes a simple semi-active control algorithm for a base-isolated structure with an MR damper. The algorithm, in which the MR damper's hysteresis shape is controlled, aims to reduce the isolator's displacement without increasing the acceleration responses of the upper structures. The second part of this paper covers the properties of an MR fluid and an MR damper developed for a base-isolated model structure. The damper has a nominal capacity of 40kN, which can be adjusted in accordance with the applied magnetic fields. In the test, the damper is subjected to cyclic sinusoidal displacements with different amplitudes, velocities and magnetic field intensities. The last part describes shaking table tests carried out using the MR damper and the base-isolated model structure. It is confirmed that the proposed semi-active control method is effective in reducing the isolator's displacement without increasing the acceleration responses. © 2002 SPIE · 0277-786X/02/$15.00.
2002年, Proceedings of SPIE - The International Society for Optical Engineering, 4696, 352 - 362, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(学術雑誌)
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研究論文(研究会,シンポジウム資料等)
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研究論文(国際会議プロシーディングス)
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研究論文(国際会議プロシーディングス)
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研究論文(学術雑誌)
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研究論文(大学,研究機関等紀要)
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研究論文(国際会議プロシーディングス)
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研究論文(大学,研究機関等紀要)
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研究論文(国際会議プロシーディングス)
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研究論文(国際会議プロシーディングス)
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研究論文(学術雑誌)
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学位論文(修士)
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研究論文(国際会議プロシーディングス)
This paper outlines shaking table tests and their results for an active seismic response control system that uses fuzzy optimal logic (FOL). The test results confirmed the validity of the vibration control effect of this seismic response control system. The results of this study lead to two conclusions, that the effectiveness of this FOL control system can be increased by modifying the membership function, and that the results of seismic response control tests can be qualitatively evaluated by simple simulation methods. © 1997 Elsevier Science Ltd.
Elsevier BV, 1998年, Engineering Structures, 20 (3), 164 - 175, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
[査読有り]
研究論文(国際会議プロシーディングス)
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研究論文(学術雑誌)
[査読有り]
研究論文(研究会,シンポジウム資料等)
[査読有り]
研究論文(国際会議プロシーディングス)
The authors have presented Ultimate Response Analysis (U.R.A.) by which one can evaluate earthquake responses of structures according to the principle of the ultimate energy equilibrium. In this analysis, response behaviours of structures are classified into the following two extreme typical cases, i.e., monotonic and cyclic responses. The former is calculated by Pulse Response Analysis (P.R.A.) and the latter by Finite Resonance Response Analysis (F.R.R.A.). In this report, an evaluation method of damages of elasto-plastic structures by the U.R.A. is proposed from the comparison of the results of the U.R.A. with those of usual time-history dynamic earthquake response analysis (E.R.A.). The followings are concluded : (1) Damage factor (D_u) by U.R.A. based on the assumption in Sect. 4-3is safe side evaluation as compared with damage factor (D_e) by E.R.A. (cf. Sect. 4-5, Figs.10-13) (2) The damage duration for F.R.R.A. (t^p_
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研究論文(学術雑誌)
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研究論文(国際会議プロシーディングス)
講演資料等(セミナー,チュートリアル,講習,講義他)
講演資料等(セミナー,チュートリアル,講習,講義他)
講演資料等(セミナー,チュートリアル,講習,講義他)
講演資料等(セミナー,チュートリアル,講習,講義他)
The dynamic characteristics of mid-story isolated buildings and seismic response reduction due to a semi-active control system were investigated using a three-lumped-mass model that simplified the sixteen story building with an isolation layer in the sixth story and that model. A semi-active control method using a rotary inertia mass damper filled with magnetorheological fluid (MR fluid) was proposed. The damper shows both mass amplification effect due to rotational inertia and variable damping effect due to the MR fluid. The damping force is controlled by the strength of the magnetic field that is applied to the MR fluid. It is determined by using the electric current, which is calculated by the proposed semi-active control method based on the velocity of the isolation layer relative to the layer just underneath it. Real-time hybrid tests using an actual damper and simulations using a building model were conducted to check the damper model; the test results were in good agreement with the simulation results. The simulation results suggest that the response displacement of the structure above the isolation layer is significantly reduced, without increasing the response acceleration of the entire structure against near-fault pulse and long-period ground motions. The proposed semi-active control using an MR rotary inertia mass damper was confirmed to be effective for mid-story isolated buildings.
一般社団法人日本機械学会, 2015年06月22日, 「運動と振動の制御」シンポジウム講演論文集, 2015 (14), 158 - 162, 日本語講演資料等(セミナー,チュートリアル,講習,講義他)
講演資料等(セミナー,チュートリアル,講習,講義他)
講演資料等(セミナー,チュートリアル,講習,講義他)
研究発表ペーパー・要旨(国際会議)
講演資料等(セミナー,チュートリアル,講習,講義他)
Semi-active control using a variable damper stabilizes building responses in an earthquake better than the conventional passive control. This paper used variable hydraulic damper. The servo valve of variable hydraulic damper controls the oil flow between two rooms of the cylinder divided by the piston. As the first step of the research, in order to evaluate the performance expected from the theoretical study, a dynamic loading test was conducted. Next, authors conducted experiment by the base-isolated specimen of two-degree-of-freedom structure. Finally, the damping performance and control characteristics of variable hydraulic damper were verified.
一般社団法人日本機械学会, 2007年09月25日, Dynamics & Design Conference, 2007, "123 - 1"-"123-5", 日本語講演資料等(セミナー,チュートリアル,講習,講義他)
講演資料等(セミナー,チュートリアル,講習,講義他)
This paper provides the experiments on semi-active control of a 3-story base-isolated structure using a magneto rheological (MR) damper. Three kinds of experiments were carried out for the following methods using the optimal control theory; (i) feedforward control method considering both time delay of MR damper and characteristics of earthquakes, (ii) feedforward control method considering characteristics of earthquakes only, and (iii) feedback control method. From the results of the experiments is was verified that MR damper could reduce acceleration and story drift responses of the structure in comparison with the case without any control. Among the adopted three control methods, the case (i) achieved the best performance.
一般社団法人日本機械学会, 2003年09月15日, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2003, 110 - 110, 日本語Research and development of the variable damper using magnetorheological fluid (MR damper) is carried out in the fields with various, brakes, clutch, and vibration response control system etc. The rheological properties of the fluids can be changed dramatically by applying a magnetic field, and this behavior can be applied to control dynamic properties of some building structures. In this paper, the fundamental characteristic was grasped by the dynamic loading tests. And, the shaking table test by one-degree-of-freedom system was carried out, and performance and controllability of the MR damper were verified.
一般社団法人日本機械学会, 2003年09月15日, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2003, 310 - 310, 日本語講演資料等(セミナー,チュートリアル,講習,講義他)
MR dampers have been attracting great research interest as variable dampers that are necessary for semi-active vibration control systems in recent years. The MR damper is a kind of hydraulic viscous damper, in which a magneto-rheological fluid (or simply MR fluid) inside the damper alters its viscosity according to the intensity of the applied magnetic field. The MR dampers have electromagnets that control the generation of a magnetic field. The viscous force generated in the damper can be easily controlled by simply adjusting the applied electric power to the electromagnets. This paper deals with dynamic performances of a large capacity MR damper developed for applying to a real base-isolated building.
一般社団法人日本機械学会, 2003年, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2003, 367 - 367, 日本語研究発表ペーパー・要旨(国際会議)
研究発表ペーパー・要旨(国際会議)
研究発表ペーパー・要旨(国際会議)
講演資料等(セミナー,チュートリアル,講習,講義他)
研究発表ペーパー・要旨(国際会議)
会議報告等
研究発表ペーパー・要旨(国際会議)
研究発表ペーパー・要旨(国際会議)
This paper deals with a development of a magneto-rheological (MR) fluid damper as the semi-active control device. MR fluid is the one of the controllable fluid. MR fluid responds applied magnetic fields and shows the characteristics of the typical Bingham fluid which has the yield stress. The intensity of the applied magnetic field can change the level of the yield stress. The MR fluid damper developed in this study has the nominal capacity of 20kN. A new magnetizing system is adopted for this MR fluid damper. Various dynamic loading tests have been carried out using of the vibration-testing machine to verify the damping characteristics of the developed MR fluid damper. As the experimental test results, it is verified that the damping force is controllable by adjusting the intensity of the magnetic field. Furthermore, a simple analytical model is proposed to simulate the behavior of the MR fluid damper, and the simulation and the experimental results are compared.
一般社団法人日本機械学会, 2000年09月01日, Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D, 2000, 398 - 398, 日本語研究発表ペーパー・要旨(国際会議)
研究発表ペーパー・要旨(国際会議)
記事・総説・解説・論説等(学術雑誌)
講演資料等(セミナー,チュートリアル,講習,講義他)
講演資料等(セミナー,チュートリアル,講習,講義他)
研究発表ペーパー・要旨(国際会議)
講演資料等(セミナー,チュートリアル,講習,講義他)
講演資料等(セミナー,チュートリアル,講習,講義他)
記事・総説・解説・論説等(学術雑誌)
講演資料等(セミナー,チュートリアル,講習,講義他)
記事・総説・解説・論説等(学術雑誌)
記事・総説・解説・論説等(学術雑誌)
記事・総説・解説・論説等(学術雑誌)
研究発表ペーパー・要旨(国際会議)
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口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
本研究は、アクティブ・セミアクティブ制御を用いて、大振幅地震動に対して、人命保護のみならず、建物の損傷を制御し、重要な機能を維持する方法を提案することを目的とする。構造部材(骨組や免震積層ゴム)が非線形化した後の挙動に対してもアクティブ・セミアクティブ制御の効果を検証するために、2つの加振装置によるリアルタイム・ハイブリッドシミュレーション(RTHS)による検証システム(デュアルRTHSシステム)を提案した。研究項目は、1)デュアルRTHSシステムの開発、2)非線形セミアクティブ免震構造の提案、3)大質量比アクティブマスダンパー(大質量比AMD)制振構造の提案である。 これに対し平成30年度は、1)デュアルRTHSシステムを開発し、その動作を確認し、続いて2)非線形セミアクティブ免震構造の提案を行った。 構築したデュアルRTHSとは、コンピュータ(DSP)内の建物モデルに地震動を入力し時刻歴応答解析を行い、得られた免震層の応答変位をアクチュエータで再現し積層ゴムを加振し、振動台で再現しセミアクティブ制御ダンパー(MRダンパー)を加振するものである。このときアクチュエータへは振動台側のコントローラからLANケーブルを通じて指令が送られる。そして積層ゴムの復元力とMRダンパーの減衰力をロードセルでそれぞれ計測し、DSP内建物モデルの運動方程式に代入して応答解析と制御演算を行う。これらの操作は500Hz間隔で繰り返される。 このデュアルRTHSを使用し、積層ゴムがハードニングを生じる非線形領域で応答する免震構造の応答をセミアクティブ制御で低減する実験を行った。その結果、積層ゴムの非線形挙動時において、提案したセミアクティブ制御則によって、線形挙動時と同等またはそれ以上のセミアクティブ制御の効果が得られることが確認できた。
競争的資金
生活と国土の基盤となる次世代インフラの再定義・新たな概念の検討を目的に、神戸大学内の異分野交流、国内外における連携研究のネットワーク形成を推進した。共通テーマとして次世代の環境ビジョンとそれに至る社会戦略を設定し、持続的環境設計学の構築に向けた研究目標に向かって、(1)震災復興に現れた新たな社会インフラ問題、(2)ビックデータを用いたスマートインフラ評価、(3)レジリエントな建築・土木構造の次世代融合研究企画及び国際的ネットワークの構築、(4)インフラ整備の見える化を推進すべく民間、官公庁とのコラボレーションを進め、研究ネットワークづくりを推進した。
パルス性地震動と長周期地震動に対する免震構造の安全性と機能性を高めるために、床応答加速度と応答変位を低減することを目的とした。磁気粘性流体(MR流体)を用いて粘性を可変にできる回転慣性質量ダンパー(MR回転慣性質量ダンパー)を製作し、解析およびリアルタイムハイブリッド実験によって、制御効果を検証した。 セミアクティブ制御により、標準的な入力地震動の他、断層近傍のパルス性地震動や長周期地震動など建築基準法の水準を超える多様な地震動に対して、最大床応答加速度を平均6%程度、最大応答変位を平均28%程度低減するなど、床応答加速度を抑制しながら、免震層の応答変位を低減できることが明らかになった。
セミアクティブ制御装置であるMRダンパー(可変ダンパーの一種)だけを試験器で加振して制御力を検出し、制御対象の構造物が制御された応答をコンピュータによるシミュレーションで求め、その応答変位と応答速度を試験器で制御装置に再現すると同時に制御計算も行いMRダンパーを制御するというリアルタイム・ハイブリッド実験手法を確立した。これによってセミアクティブ制振構造の応答低減効果を検証した。このとき等価サイクル数を減衰性能を評価する指標として採用し、その有効性を示した。
1被災前後の環境、被災・復興の諸過程図化、集落環境の物的復興と社会変化・支援制度の解析。2住宅被害(人的被害)の実態解明と建築及び環境との関連の解明。3最激甚被災地域における地盤条件の解明。4枠組み壁組積造(Confined Masonry)の工法的妥当性の検討。5伝統的木構造であり歴史的建造物であり、軸組的に脆弱なPendopo の形態を損ねない制震技術の開発。6竹造建築の可能性を追求しその実験モデルの現地建設。7住宅復興過程の解明、外部支援供与宅の適合性の計画学的・環境工学的な検討。
競争的資金
競争的資金
制振ダンパーとして、履歴型ダンパーと粘性型ダンパーを研究対象とした。
平成17年度の各種ダンパーの単体載荷実験から得られた、制振ダンパーの必要なエネルギ散逸特性や特定した数学モデルに基づき、平成18年度は、履歴ダンパーで連結された連結制振構造物の必要なエネルギ散逸特性や接続された構造物群の制振効果を確認するため、エネルギ散逸要素に対する載荷実験をオンラインで結合した地震応答実験によって行った。まず、低降伏点鋼を用いたせん断パネル型履歴ダンパーについて、パネル部の厚さが薄い場合,パネル部の面外座屈による局所的な耐力低下が全体連結構造物に及ぼす影響を調べ、その影響が少ない既存のスケルトン・シフトモデルを用いた応答解析結果を準用することが出来ることが判明した。また、梁間方向の伸縮と上下動、桁行き方向の水平変位に対して履歴減衰を付加することが可能な多方向ダンパー(鋼管ダンパー)を製作し、地震時の挙動を調べた。鋼管ダンパーの形状の特性によって、鋼管ダンパーの亀裂進展による耐力低下は入力振幅の大きさ及び入力波形によって極めて大きく変動することを示し、等価単調載荷曲線を用いてスケルトン・シフトモデルの適用範囲を提案した。そして摩擦ダンパーについて、連結制振部材としての適用可能性を検討した。せん断型摩擦ダンパーを完全弾塑性モデルでモデル化して地震時の応答挙動を制度良く追跡できることを示し、卓越する変位低減効果を有することが明らかになった。更に、上のいずれの履歴型ダンパーに対しても、連結制振性能曲線を作成し、これからの連結制振構造物の設計時に有効な指標(ダンパーの剛性と耐力)や制振効果の予測に関する情報を確認した。
粘性型ダンパーについては、オイルダンパーと粘弾性ダンパーを適用し、17年度に実施した単体特性試験の結果から得られたダンパーのモデルを用いて、地震応答解析を実施した。17年度は、構造モデルは弾性であったが、より現実の建築物への適用性を高めるために、弾塑性系の構造物、および多質点系の構造物に適用した解析を行った。その結果、新設S造の固有周期が短い(ブレースの設置などによって剛性が高い)場合は、新設S造の質量を既存RC造の0.25倍以上となるようにし、既存RC造の重量1000kNあたり、粘性減衰係数C_d=5〜20kNs/cm程度のオイルダンパー、または等価粘性減衰係数C_
競争的資金
近年、建築構造に関する社会のニーズが多様化し、高度な安全性のみならず、高い機能性や居住性も求められている。本研究では強風時や地震時でも機能を果たすことや地震時でも恐怖感を与えず快適さを損なわない性能を付与するために、実際の免震建築物に適用できるMRダンパーを開発しそれを制御する有効な制御システムを構築し、実在する免震建築物こ設置して一定期間観測を行い、その効果を検証し適用可能性を明らかにした。 まず実際の免震建築物に適用しうる、ストローク±475mm、最大減衰力400kNのMRダンパーを開発した。このようなMRダンパーを実現できるダンパーの形式、必要な電磁石の大きさ、必要な電源容量等の検討を行った。 次に、制御アルゴリズムの研究開発を行った。これまでに基本的な研究は行っているが、実際の建築物に設置するために、より安定性を高めたアルゴリズムを開発する必要があった。アルゴリズムの開発に関しては建築研究所で行い、実際の建築物に設置する制御装置を購入するとともに、制御の安定性を高めた。また制御アルゴリズムの検証のために振動台実験を実施し、制御アルゴリズムの安定性を確認した。 その後、実建築物の地震応答シミュレーションを実施した。シミュレーションの結果、本課題の目標とした居住性および機能維持が課題となる中程度の地震動に対しては、応答変位を低減して安全性を向上させながら、絶対加速度も低減して居住性・機能維持性能を向上できる結果となり、MRダンパーを設置した効果が期待できることがわかった。複数の地震波に対してシミュレーションを行ったが、いずれの場合も併設されているオイルダンパーが初期減衰定数の範囲(リリーフ荷重以下)にとどまり、MRダンパーとオイルダンパーによって、より効果的な性能向上が行えることが分かった。 その後、地震応答観測を継続している。