基于幂指数法的地震模拟振动台频域前馈补偿方法

针对地震模拟振动台受到系统和试件非线性等因素影响,导致波形再现精度不高的问题,提出基于幂指数法的地震模拟振动台频域前馈补偿方法以提高振动台的控制效果,通过数值仿真和实际振动台试验对该方法的控制性能进行研究。研究结果表明：基于幂指数法的地震模拟振动台频域前馈补偿方法能够快速收敛,迭代次数较少,可以大幅提高振动台的波形复现精度,能够提高振动台的控制性能。     

基于专家经验的振动台控制参数自整定方法研究

地震模拟振动台控制系统的控制参数较多,其参数手动整定费时费力,尤其对于多振动台台阵系统,其手动整定难度很大.基于上述问题,根据专家进行系统调试的经验,提出了一种振动台控制参数自整定策略,分析了手动整定中各参数对系统性能的影响,给出了自整定算法的整定规则,并通过Matlab仿真进行振动台的控制参数自动整定.通过比较自整定参数和理论计算参数下的时频域特性,验证了本文所给出的自整定算法.结果表明,该方法具有简单实用及较好的实用价值,可供振动台参数自整定研究参考和借鉴.     

高阶单步法控制MR智能隔震系统的试验研究

高阶单步法已成功地应用于结构非线性分析及考虑时滞的主动控制等，显示了它的稳定、精度高和计算迅速等特点。磁流变阻尼器是一种性能优良的智能阻尼器，它具有阻尼力可调范围宽、响应迅速且所需能量很少的特点。本文将磁流变（MR）阻尼器与普通橡胶隔震支座相结合，采用高阶单步算法和两种控制策略对结构进行振动控制。数值模拟分析与振动台试验结果表明：由MR阻尼器提供可调阻尼力的智能隔震控制系统能有效克服被动隔震最优控制频带窄的缺点，对较宽频域范围不同大小的地震激励均能提供最优控制。同时也表明该控制算法是一种能用于结构实际控制的变阻尼有效算法。     

伺服阀对地震模拟振动台控制性能影响及控制参数自整定

振动台控制系统设计时对物理系统进行了两个基本假设:伺服阀线性、台面和负载刚性。这样得到的控制系统频带较窄、时滞大,还有可能出现控制系统不稳定。本文通过系统建模,主要分析了伺服阀对振动台控制性能的影响:伺服阀频率特性限制了其控制精度。设计了前馈补偿环节、控制系统参数自整定算法修正系统控制性能,实例仿真结果表明:修正后的算法扩宽了系统频带,提高了地震记录的再现精度。     

海域天然气水合物的地震研究进展

海域天然气水合物的地震研究是在岩石物性分析成果的指导下,用地震技术进行真假BSR的识别和含水合物沉积层物性预测.海域天然气水合物地震研究的进展主要表现在：物性分析理论模型由简单模型发展到最大程度模拟实际情况的复杂模型;地震勘探方法已由常规的单道、多道地震发展到多频地震、高分辨率二维、三维地震和海底多分量地震;地震资料处理由常规处理发展到突出BSR特征的“三高”和叠前时间偏移处理;从利用速度、振幅结构研究识别天然气水合物发展到AVO、多属性判别、多弹性参数和多物性参数反演识别天然气水合物、预测其物性参数.这些新技术、新方法的应用,加快了海域天然气水合物调查进度,提高了天然气水合物地球物理识别的可靠性.     

安装复合MR阻尼器的结构振动台试验研究

对不同控制策略下安装有复合MR(磁流变)阻尼器的模型结构进行了振动台试验研究.在El Centro地震动激励下,基于线性二次高斯(LQG)和广义预测(GP)两种控制算法,针对半主动控制系统、MR阻尼器以恒定电流(-0.5A(Passive-on 1)、0A(Passive-off)、2A(Passive-on 2)的控制系统,以及由半主动控制方式和基础隔震组合而成的混合控制系统,在WINCON/SIMULINK实时控制软件平台下对一个1:4的三层钢框架模型进行了地震模拟振动台试验.试验结果表明:基于复合MR阻尼器的控制系统是有效的,无论是被动控制、半主动控制还是混合控制,都显著降低了模型结构各层的加速度、位移响应;复合MR阻尼器在不通入电流时具有一定的被动控制效果;采用考虑时滞自补偿的广义预测控制效果要好于LQG控制,并且这两种控制策略的都能以较被动控制小的控制力达到较好的控制效果.     

结构主动减震控制研究进展

本文阐述了结构主动减震控制研究进展,内容包括：７种有代表性的主动控算法,主动控制结构的振动台试验与工程应用及地震考验,土与结构相互作用效应对结构主动控制算法及效果的影响以及目前追切需要进一步研究的课题。     

三向地震作用下砌体结构抗震性能研究

本文首先介绍了两个砌体结构模型在三向地震作用下的地震模拟振动台试验，在此基础上，运用参数识别技术，对试验数据进行了参数识别计算，最后，分析了三向地震作用对砌体结构抗震性能的影响。     

STFT变换在高层框架结构地震损伤程度识别中的应用

为了研究地震作用下高层框架结构的损伤程度信息,以结构刚度折减率为损伤程度指标,以结构的频率变化率为损伤程度识别参数,采用Matlab模拟结构在不同的损伤程度指标下的加速度响应数据,利用短时傅里叶变换方法对响应数据分析得到结构的模态参数,从而建立损伤程度指标与结构模态参数的函数关系。将损伤结构的模态参数代入函数关系式计算结构的损伤程度指标。采用同济大学振动台试验数据,利用此方法识别结构的损伤程度与振动台试验观察到的损伤程度高度吻合。     

电磁驱动AMD系统控制结构地震响应的振动台试验

本文在此前一系列有关新型电磁驱动AMD控制系统力学建模、性能试验和控制策略研究的基础上,进行了结构地震响应控制的小型振动台试验研究。首先,针对配置了电磁驱动AMD控制系统的Quanser标准两层剪切型框架结构模型,建立了无控计算模型,通过正弦扫频试验验证了模型参数,从而为结构振动主动控制试验研究提供了准确的被控对象模型;其次,设计了电磁驱动AMD控制系统基于极点配置控制算法的试验控制策略和状态观测器,通过数值分析验证了状态观测器估计结果的准确性;最后,在完成以上各项准备工作的基础上,分别对结构输入了典型Benchm ark标准地震动,进行振动台试验,试验结果表明电磁驱动AMD控制系统对结构的地震响应具有显著的控制效果,验证了该新型系统应用于结构振动控制的有效性和可行性。     

Linear dynamic modeling of a uni‐axial servo‐hydraulic shaking table system

This paper focuses on the development of a linear analytical model (even though servo‐hydraulic actuation systems are inherently non‐linear, especially for large amplitude simulations — near the performance capacity of the system — linearized models proved experimentally to be quite effective overall in capturing the salient features of shaking table dynamics) of a uni‐axial, servo‐hydraulic, stroke controlled shaking table system by using jointly structural dynamics and linear control theory. This model incorporates the proportional, integral, derivative, feed‐forward, and differential pressure gains of the control system. Furthermore, it accounts for the following physical characteristics of the system: time delay in the servovalve response, compressibility of the actuator fluid, oil leakage through the actuator seals and the dynamic properties of both the actuator reaction mass and test structure or payload. The proposed model, in the form of the total shaking table transfer function (i.e. between commanded and actual table motions), is developed to account for the specific characteristics of the Rice University shaking table. An in‐depth sensitivity study is then performed to determine the effects of the table control parameters, payload characteristics, and servovalve time delay upon the total shaking table transfer function. The sensitivity results reveal: (a) a potential strong dynamic interaction between the oil column in the actuator and the payload, and (b) the very important effect of the servovalve time delay upon the total shaking table transfer function. Copyright © 2000 John Wiley & Sons, Ltd.     

SEISMIC TESTING OF A BUILDING STRUCTURE WITH A SEMI-ACTIVE FLUID DAMPER CONTROL SYSTEM

This paper describes shaking table tests of a multi-storey scale-model building structure subjected to seismic excitation and controlled by a semi-active fluid damper control system. The semi-active dampers were installed in the lateral bracing of the structure and the mechanical properties of the dampers were modified according to control algorithms which utilized the measured response of the structure. A simplified time-delay compensation method was developed to account for delays within the control system. The results of the shaking table tests are presented and interpreted and analytical predictions are shown to compare reasonably well with the experimental results. © 1997 John Wiley & Sons, Ltd.     

地铁车站结构大型振动台试验与数值模拟的比较研究

根据可液化土层上土-地铁车站结构动力相互作用大型振动台模型试验结果,以软件ABAQUS为平台,将地基土-地铁车站结构体系视为平面应变问题,采用记忆型嵌套面黏塑性动力本构模型模拟土体的动力特性,采用混凝土动塑性损伤模型模拟车站结构混凝土的动力特性,建立了土-地铁车站结构非线性动力相互作用的有限元分析模型,对各种试验工况下地基土-地铁车站结构体系的地震反应进行了数值模拟,并与试验结果进行了对比,结果表明:数值模拟与振动台模型试验结果基本一致,体现出了相似的规律性,相互印证了计算分析的力学建模和振动台试验结果的正确性。     

A substructure shaking table test for reproduction of earthquake responses of high‐rise buildings

When subjected to long‐period ground motions, high‐rise buildings' upper floors undergo large responses. Furniture and nonstructural components are susceptible to significant damage in such events. This paper proposes a full‐scale substructure shaking table test to reproduce large floor responses of high‐rise buildings. The response at the top floor of a virtual 30‐story building model subjected to a synthesized long‐period ground motion is taken as a target wave for reproduction. Since a shaking table has difficulties in directly reproducing such large responses due to various capacity limitations, a rubber‐and‐mass system is proposed to amplify the table motion. To achieve an accurate reproduction of the floor responses, a control algorithm called the open‐loop inverse dynamics compensation via simulation (IDCS) algorithm is used to generate a special input wave for the shaking table. To implement the IDCS algorithm, the model matching method and the H_∞ method are adopted to construct the controller. A numerical example is presented to illustrate the open‐loop IDCS algorithm and compare the performance of different methods of controller design. A series of full‐scale substructure shaking table tests are conducted in E‐Defense to verify the effectiveness of the proposed method and examine the seismic behavior of furniture. The test results demonstrate that the rubber‐and‐mass system is capable of amplifying the table motion by a factor of about 3.5 for the maximum velocity and displacement, and the substructure shaking table test can reproduce the large floor responses for a few minutes. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis of shaking table-structure interaction effects during seismic simulation tests

An analytical model is developed to evaluate performance characteristics of unidirectional seismic simulators (shaking tables). The validity of the model is verified with experimental measurements of the frequency response of the shaking table at the Catholic University of Peru. Interaction effects between shaking table and structure are first studied by analysing the response of a two DOF (degree of freedom) oscillator with mechanical properties representative of the actuator-table-structure system. A single DOF viscoelastic oscillator representing the structural test specimen is then included in the analytical model of the seismic simulator, and the behaviour of the combined system is evaluated, in the frequency domain, in terms of response stability and accuracy of reproduction of the command signal. Numerical simulations of system response under different load conditions are subsequently performed in order to study the influence of shaking table and test structure characteristics on the interaction phenomenon. The results obtained explain some of the performance degradation observed in seismic simulation tests involving very heavy structures and provide guidelines for the design of more reliable shaking table systems.     

简易单向专用地震模拟振动台的研制

振动台实验方法是目前抗震研究中的重要手段之一。作者在碎石桩加固液化地基效果的试验研究中,利用从美国MTS公司引进的电液伺服加载试验系统,建成了一个简易单向专用振动台。主要介绍在振动台设计方面遇到的技术难题及其解决途径。主要包括振动台基础、台面和作动器连接部件、台面支撑系统和侧面导向系统材料的正确选择、设计和制作等。文中所采用的技术措施对试验成功起到了保障作用,研制出的振动台试验系统还可以应用于其它岩土地震问题的试验研究。     

Control strategies and experimental verifications of the electromagnetic mass damper system for structural vibration control

The electromagnetic mass damper （EMD） control system, as an innovative active control system to reduce structural vibration, offers many advantages over traditional active mass driver/damper （AMD） control systems. In this paper, studies of several EMD control strategies and bench-scale shaking table tests of a two-story model structure are described. First, two structural models corresponding to uncontrolled and Zeroed cases are developed, and parameters of these models are validated through sinusoidal sweep tests to provide a basis for establishing an accurate mathematical model for further studies. Then, a simplified control strategy for the EMD system based on the pole assignment control algorithm is proposed. Moreover, ideal pole locations are derived and validated through a series of shaking table tests. Finally, three benchmark earthquake ground motions and sinusoidal sweep waves are imposed onto the structure to investigate the effectiveness and feasibility of using this type of innovative active control system for structural vibration control. In addition, the robustness of the EMD system is examined. The test results show that the EMD system is an effective and robust system for the control of structural vibrations.     

土-结构体系振动台模型试验中土层边界影响问题

通过数值模拟和模型试验,初步探讨了土－结构相互作用体系模型试验中土层侧向边界的影响情况,研究了土层边界处加入橡胶层后的作用,从而为土－结构相互作用体系模型试验设计提供了一些依据。