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1.
一种新型混合控制技术的振动台模型试验研究 总被引：1，自引：1，他引：0
本文提出了基底隔震和上部结构变刚度／阻尼半主动控制结合的一种新型混合控制型式,并且通过小型电磁振动台模型试验来研究其控制效能,为其今后更进一步理论和实验研究奠定基础。 相似文献
2.
In this paper, a new system of semi active structural control with active variable stiffness and damping (AVSD) is suggested.
This new system amplifies the structural displacement to dissipate more energy, and in turn, effectively reduces the structural
response in the case of relatively small story drifts, which occur during earthquakes. A predictive instantaneous optimal
control algorithm is established for a SDOF structure equipped with an AVSD system Comparative shaking table tests of a 1/4
scale single story structural model with a full scale control device have been conducted. From the experimental and analytical
results, it is shown that when compared to structures without control or with the active variable stiffness control alone,
the suggested system exhibits higher efficiency in controlling the structural response, requires less energy input, operates
with higher reliability, and can be manufactured at a lower cost and used in a wider range of engineering applications. 相似文献
3.
高层建筑结构质量动力评定技术研究 总被引：1，自引：0，他引：1
李杰 《地震工程与工程振动》2001,21(4):125-131
结构质量评价对我国住宅产业的发展具有重要意义.本文提出一种基于复合反演算以别高层建筑刚度和阻尼的型动力评定技术.给出了两种解决混合反演问题的时域方法,并通过实例诠释了该方法在局部振动和环境激励下应用的可行性,将此技术结合传统的材料强度测试及静态无损捡测技术,可建立一种包含动力检测方法的新型工程质量评定体系. 相似文献
4.
Numerical simulations of a highway bridge structure employing passive negative stiffness device for seismic protection 
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下载免费PDF全文 Navid Attary Michael Symans Satish Nagarajaiah Andrei M. Reinhorn Michael C. Constantinou Apostolos A. Sarlis Dharma T. R. Pasala Douglas Taylor 《地震工程与结构动力学》2015,44(6):973-995
A new passive seismic response control device has been developed, fabricated, and tested by the authors and shown to be capable of producing negative stiffness via a purely mechanical mechanism, thus representing a new generation of seismic protection devices. Although the concept of negative stiffness may appear to be a reversal on the desired relationship between the force and displacement in structures (the desired relationship being that the product of restoring force and displacement is nonnegative), when implemented in parallel with a structure having positive stiffness, the combined system appears to have substantially reduced stiffness while remaining stable. Thus, there is an ‘apparent weakening and softening’ of the structure that results in reduced forces and increased displacements (where the weakening and softening is of a non‐damaging nature in that it occurs in a seismic protection device rather than within the structural framing system). Any excessive displacement response can then be limited by incorporating a damping device in parallel with the negative stiffness device. The combination of negative stiffness and passive damping provides a large degree of control over the expected performance of the structure. In this paper, a numerical study is presented on the performance of a seismically isolated highway bridge model that is subjected to various strong earthquake ground motions. The Negative Stiffness Devices (NSDs) are described along with their hysteretic behavior as obtained from a series of cyclic tests wherein the tests were conducted using a modified design of the NSDs (modified for testing within the bridge model). Using the results from the cyclic tests, numerical simulations of the seismic response of the isolated bridge model were conducted for various configurations (with/without negative stiffness devices and/or viscous dampers). The results demonstrate that the addition of negative stiffness devices reduces the base shear substantially, while the deck displacement is limited to acceptable values. This assessment was conducted as part of a NEES (Network for Earthquake Engineering Simulation) project which included shaking table tests of a quarter‐scale highway bridge model. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
5.
This study presents a fast algorithm for collapse behavior simulation of space truss structures under extreme earthquake excitation by introducing the Woodbury formula to efficiently solve the structural response caused by material and geometric nonlinearity (hybrid nonlinearity). The Woodbury formula, which is an efficient tool in mathematics for solving low-rank perturbation problems, has successfully been used to improve the efficiency of local material nonlinear analysis but still has difficulties with seismic collapse analysis in which geometric nonlinearity should be considered. In this study, by implementing stiffness matrix decomposition according to the unchanged reference configuration, the effects of hybrid nonlinearity on the change in tangent stiffness of truss structures are uniformly formulated in the form of hybrid nonlinear perturbation to the reference elastic stiffness. Thus, a hybrid nonlinearity separated governing equation can be established, in which the hybrid nonlinear behaviors are depicted by the additional nonlinear degrees of freedom (NLDOFs) separated from the reference system. This allows for employing the Woodbury formula to perform seismic collapse analysis of space truss structures for avoiding the repeated updating of the global stiffness. To overcome the adverse effect of the large NLDOF number caused by the global characteristics of geometric nonlinearity on the efficiency advantages of the Woodbury formula during seismic collapse analysis, an element state judgment strategy and an adaptive restart mechanism are presented to activate only a small number of NLDOFs within critical local regions. The accuracy and efficiency of the proposed method are verified by two numerical examples. 相似文献
6.
结构参数控制器优化分布的一种计算方法 总被引：1，自引：0，他引：1
参数控制器就是通过改变受控结构的参数（阻尼或刚度）来减小其振动响应的控制系统。本文以高层建筑结构为研究对象,推导了在地震作用下结构层间位移响应的计算方法,并根据其计算结果确定参数控制器的优化分布,文中还以某１０层建筑结构为例进行了仿真计算。 相似文献
7.
地震力作用下影响巨子型有控结构的动力参数研究 总被引：3，自引：0，他引：3
附加柱刚度与附加阻尼为影响巨子型有控结构抗震性能的两个重要参数。本文基于随机振动理论探讨水平地震作用下附加柱刚度及附加阻尼对巨、子结构动态特性的影响,分析附加阻尼与附加柱间的制约关系,并对比研究传统巨型框架结构、巨子型有控结构安装流体阻尼器前后的响应功率谱变化。结果表明:巨子型有控结构具有极好的抗震性能,安装合理的附加阻尼后,其抗震能力得到进一步提高;附加柱刚度变化不但影响巨、子结构动力响应,而且会导致最优附加阻尼区间迁移。因此,巨子型有控结构具有广阔的发展空间,实际设计中应充分考虑附加柱与附加阻尼的相互影响。 相似文献
8.
In this paper, a semiactive variable stiffness （SVS） device is used to decrease cable oscillations caused by parametric excitation, and the equation of motion of the parametric vibration of the cable with this SVS device is presented. The ON/OFF control algorithm is used to operate the SVS control device. The vibration response of the cable with the SVS device is numerically studied for a variety of additional stiffness combinations in both the frequency and time domains and for both parametric and classical resonance vibration conditions. The numerical studies further consider the cable sag effect. From the numerical results, it is shown that the SVS device effectively suppresses the cable resonance vibration response, and as the stiffness of the device increases, the device achieves greater suppression of vibration. Moreover, it was shown that the SVS device increases the critical axial displacement of the excitation under cable parametric vibration conditions. 相似文献
9.
Initial versus tangent stiffness‐based Rayleigh damping in inelastic time history seismic analyses 下载免费PDF全文
下载免费PDF全文 In the inelastic time history analyses of structures in seismic motion, part of the seismic energy that is imparted to the structure is absorbed by the inelastic structural model, and Rayleigh damping is commonly used in practice as an additional energy dissipation source. It has been acknowledged that Rayleigh damping models lack physical consistency and that, in turn, it must be carefully used to avoid encountering unintended consequences as the appearance of artificial damping. There are concerns raised by the mass proportional part of Rayleigh damping, but they are not considered in this paper. As far as the stiffness proportional part of Rayleigh damping is concerned, either the initial structural stiffness or the updated tangent stiffness can be used. The objective of this paper is to provide a comprehensive comparison of these two types of Rayleigh damping models so that a practitioner (i) can objectively choose the type of Rayleigh damping model that best fits her/his needs and (ii) is provided with useful analytical tools to design Rayleigh damping model with good control on the damping ratios throughout inelastic analysis. To that end, a review of the literature dedicated to Rayleigh damping within these last two decades is first presented; then, practical tools to control the modal damping ratios throughout the time history analysis are developed; a simple example is finally used to illustrate the differences resulting from the use of either initial or tangent stiffness‐based Rayleigh damping model. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
10.
A rate‐dependent constitutive model of high damping rubber bearings: modeling and experimental verification 下载免费PDF全文
下载免费PDF全文 Yong Yuan Wei Wei Ping Tan Akira Igarashi Hongping Zhu Hirokazu Iemura Tetsuhiko Aoki 《地震工程与结构动力学》2016,45(11):1875-1892
In this study, a constitutive model of high damping rubber bearings (HDRBs) is developed that allows the accurate representation of the force–displacement relationship including rate‐dependence for shear deformation. The proposed constitutive model consists of two hyperelastic springs and a nonlinear dashpot element and expresses the finite deformation viscoelasticity laws based on the classical Zener model. The Fletcher–Gent effect, manifested as high horizontal stiffness at small strains and caused by the carbon fillers in HDRBs, is accurately expressed through an additional stiffness correction factor α in the novel strain energy function. Several material parameters are used to simulate the responses of high damping rubber at various strain levels, and a nonlinear viscosity coefficient η is introduced to characterize the rate‐dependent property. A parameter identification scheme is applied to the results of the multi‐step relaxation tests and the cyclic shear tests, and a three‐dimensional function of the nonlinear viscosity coefficient η with respect to the strain, and strain rate is thus obtained. Finally, to investigate the accuracy and feasibility of the proposed model for application to the seismic response assessment of bridges equipped with HDRBs, an improved real‐time hybrid simulation (RTHS) test system based on the velocity loading method is developed. A single‐column bridge was used as a test bed and HDRBs was physically tested. Comparing the numerical and RTHS results, advantage of the proposed model in the accuracy of the predicted seismic response over comparable hysteretic models is demonstrated. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
11.
Real‐time hybrid testing is a very effective technique for evaluating the dynamic responses of rate‐dependent structural systems subjected to earthquake excitation. A smart base isolation system has been proposed by others using conventional low‐damping isolators and controllable damping devices such as magnetorheological (MR) dampers to achieve specified control target performance. In this paper, real‐time hybrid tests of a smart base isolation system are conducted. The simulation is for a base‐isolated two‐degrees‐of‐freedom building model where the superstructure and the low‐damping base isolator are numerically simulated, and the MR damper is physically tested. The target displacement obtained from the step‐by‐step integration of the numerical substructure is imposed on the MR damper, which is driven by three different control algorithms in real‐time. To compensate the actuator delay and improve the accuracy of the test, an adaptive phase‐lead compensator is implemented. The accuracy of each test is investigated by using the root mean square error and the tracking indicator. Experimental results demonstrate that the hybrid testing procedure using the proposed actuator compensation techniques is effective for investigating the control performance of the MR damper in a smart base isolation system. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
12.
This paper presents a family of semi‐active control algorithms termed as active interaction control (AIC) used for seismic response control of civil structures. AIC control algorithms include active interface damping (AID), optimal connection strategy (OCS) and tuned interaction damping (TID). A typical SDOF AIC system consists of a primary structure, an auxiliary structure and an interaction element. The auxiliary structure typically has stiffness comparable to that of the primary structure while its natural frequency is much higher than that of the primary structure. Interactions between the primary and the auxiliary structures are defined by specific AIC control logic such that vibrational energy is extracted from the primary structure into the auxiliary structure during a locking phase and dissipated in the auxiliary structure in the subsequent unlocking phase. The stability of AIC control algorithms is shown using the Lyapunov direct method. The efficacy of AIC control algorithms is demonstrated by the results of numerical simulations of SDOF systems subjected to seismic ground motions. Practical issues such as sampling period and time delay are also investigated in this study. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
13.
The development and applications of a supplemental viscous damping device with active capacity are described. The system of the dampers defined as active viscous damping system (AVDS) is presented herein. Structural control principles defined here as active control theory (ACT) are used to obtain the control forces at each time step during an excitation. Control of the damping forces is possible due to a mechanical structure of the proposed AVDS and do not require the input of large power and energy. This system can be efficiently used to enhance the damping of a structure without adding in stiffness and strength. The added damping forces can be adjusted in a wide range. Its efficiency is demonstrated by a numerical simulation of a seven‐storey building subjected to earthquakes. The simulation shows that the behaviour of the damped structure with the AVDS is significantly improved compared to that of an uncontrolled system. Moreover, the response is better than that of adding either passive viscous dampers or electrorheological damping devices. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
14.
A magnetorheological (MR) damper has been manufactured and tested and a non‐linear model is discussed. The parameters for the model are identified from an identification set of experimental data; these parameters are then used to reconstruct the force vs. displacement and the force vs. velocity hysteresis cycles of the MR damper for the hysteretic model. Then experiments are conducted on a three‐storey frame model using impact excitation, which identifies dynamic parameters of the model equipped with and without the MR damper. Natural frequencies, damping ratios and mode shapes, as well as structural properties, such as the mass, stiffness and damping matrices, are obtained. A semi‐active control method such as a variable structure controller is studied. Based on the ‘reaching law’ method, a feedback controller is presented. In order to evaluate the efficiency of the control system and the effect of earthquake ground motions, both numerical analysis and shaking table tests of the model, with and without the MR damper, have been carried out under three different ground motions: El Centro 1940, Taft 1952, and Ninghe 1976 (Tangshan Earthquake in Chinese). It is found from both the numerical analysis and the shaking table tests that the maximum accelerations and relative displacements for all floors are significantly reduced with the MR damper. A reasonable agreement between the results obtained from the numerical analysis and those from the shaking table tests is also observed. On the other hand, tests conducted at different earthquake excitations and various excitation levels demonstrate the ability of the MR damper to surpass the performance of a comparable passive system in a variety of situations. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
15.
The development and the applications of an active controlled viscous damping device with amplifying braces are described. The system of the dampers, defined as active viscous damping system (AVDS), connected to an amplifying brace (AB) is presented herein. Instantaneous control theory with velocity and acceleration feedback is used to obtain the control forces at each time step during an excitation. Control of the damping forces is possible due to the mechanical structure of the proposed AVDS, and the connection to the AB. The proposed system can be efficiently used to enhance the damping of a structure without modifying its stiffness. The added damping forces can be adjusted in a wide range. The efficiency of the presented system is demonstrated by a numerical simulation of a seven‐storey building subjected to earthquakes. The simulation shows a considerable reduction of control forces required for control to the AVDS with AB, compared to the same system without AB. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
16.
Passive supplemental damping in a seismically isolated structure provides the necessary energy dissipation to limit the isolation system displacement. However, damper forces can become quite large as the passive damping level is increased, resulting in the requirement to transfer large forces at the damper connections to the structure which may be particularly difficult to accommodate in retrofit applications. One method to limit the level of damping force while simultaneously controlling the isolation system displacement is to utilize an intelligent hybrid isolation system containing semi-active dampers in which the damping coeffic ient can be modulated. The effectiveness of such a hybrid seismic isolation system for earthquake hazard mitigation is investigated in this paper. The system is examined through an analytical and computational study of the seismic response of a bridge structure containing a hybrid isolation system consisting of elastomeric bearings and semi-active dampers. Control algorithms for operation of the semi-active dampers are developed based on fuzzy logic control theory. Practical limits on the response of the isolation system are considered and utilized in the evaluation of the control algorithms. The results of the study show that both passive and semi-active hybrid seismic isolation systems consisting of combined base isolation bearings and supplemental energy dissipation devices can be beneficial in reducing the seismic response of structures. These hybrid systems may prevent or significantly reduce structural damage during a seismic event. Furthermore, it is shown that intelligent semi-active seismic isolation systems are capable of controlling the peak deck displacement of bridges, and thus reducing the required length of expansion joints, while simultaneously limiting peak damper forces. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
17.
The distinct element method (DEM) has been used successfully for the dynamic analysis of rigid block systems. One of many
difficulties associated with DEM is modeling of damping. In this paper, new procedures are proposed for the damping modeling
and its numerical implementation in distinct element analysis of rigid multi-block systems. The stiffness proportional damping
is constructed for the prescribed damping ratio, based on the non-zero fundamental frequency effective during the time interval
while the boundary conditions remain essentially constant. At this time interval, the fundamental frequency can be estimated
without complete eigenvalue analysis. The damping coefficients will vary while the damping ratio remains the same throughout
the entire analysis. A new numerical procedure is developed to prevent unnecessary energy loss that can occur during the separation
phases. These procedures were implemented in the development of the distinct element method for the dynamic analyses of piled
multi-block systems. The analysis results for the single-block and two-block systems were in a good agreement with the analytic
predictions. Applications to the seismic analyses of piled fourblock systems revealed that the new procedures can make a significant
difference and may lead to much-improved results. 相似文献
18.
The paper presents a detailed reexamination of the effects of three damping models on the inelastic seismic response of structures with massless degrees of freedom. The models considered correspond to (a) Rayleigh damping based on current properties (tangent stiffness), (b) Rayleigh damping based on initial properties, and (c) modal damping. The results suggest that some nonzero damping forces/moments at massless DOFs obtained in multistory frames for the case of Rayleigh damping with tangent stiffness may be numerical artifacts rather than a deficiency of the damping model. The results also indicate that significant artificial numerical oscillations in the velocities of the secondary components of MDOF structures are introduced when modal damping or mass-proportional damping is used. 相似文献
19.
A good artificial boundary treatment in a seismic wave grid-based numerical simulation can reduce the size of the computational region and increase the computational efficiency, which is becoming increasingly important for seismic migration and waveform inversion tasks requiring hundreds or thousands of simulations. Two artificial boundary techniques are commonly used: perfectly matched layers (PMLs), which exhibit the excellent absorption performance but impose a greater computational burden by using finite layers to gradually reduce wave amplitudes; and absorbing boundary conditions (ABCs), which have the high computational efficiency but are less effective in absorption because they employ the one-way wave equation at the exterior boundary. Naturally, PMLs have been combined with ABCs to reduce the number of PMLs, thus improving the computational efficiency; many studies have proposed such hybrid PMLs. Depending on the equations from which the ABCs are derived, there are two hybrid PML variants: the PML+unstretched ABC (UABC), in which the ABC is derived from a physical equation; or the PML+stretched ABC (SABC), in which the ABC is derived from the PML equation. Even though all the previous studies concluded that hybrid PMLs can improve the absorption performance, none of them quantified how many PMLs can be removed by combining the PML with the ABC compared with the pure PML. In this paper, we systematically study the absorption performance of the two hybrid PML variants. We develop a method to distinguish the artificial reflections from the PML-interior interface and those caused by the PML exterior boundary to accurately approximate the additional absorption achieved by using the UABC and the SABC. The reflection coefficients based on a theoretical derivation and numerical tests both show that the UABC amplifies most reflections and is not recommended in any situation; conversely, the SABC can always diminish reflections, but the additional absorption achieved by the SABC is relatively poor and cannot effectively reduce the number of PMLs. In contrast, we find that simply increasing the damping parameter improves absorption better than the PML+SABC. Our results show that the improvement in absorption achieved by combining the PML with either the SABC or the UABC is not better than that obtained by simply adjusting the damping profile of the PML; thus, combining the PML with the ABC is not recommended in practice. 相似文献
20.
This paper presents an experimental study to explore the possibility of using a hybrid platform to ensure the functionality of high‐tech equipment against microvibration and to protect high‐tech equipment from damage when an earthquake occurs. A three‐storey building model and a hybrid platform model were designed and manufactured. The two‐layer hybrid platform, on which the high‐tech equipment is placed, was installed on the first floor of the building to work as a passive platform aiming at abating acceleration response of the equipment during an earthquake and functioning as an actively controlled platform that intends to reduce velocity response of the equipment under a normal working condition. For the hybrid platform working as a passive platform, it was designed in such a way that its stiffness and damping ratio could be changed, whereas for the hybrid platform functioning as an active platform, a piezoelectric actuator with a sub‐optimal velocity feedback control algorithm was used. A series of shaking table tests, traffic‐induced vibration tests and impact tests were performed on the building with and without the platform to examine the performance of the hybrid platform. The experimental results demonstrate that the hybrid platform is feasible and effective for high‐tech equipment protection against earthquake and microvibration. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献