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1.
This paper presents a semi-active strategy for seismic protection of a benchmark cable-stayed bridge with consideration of multiple-support excitations. In this control strategy, Magnetorheological (MR) dampers are proposed as control devices, a LQG-clipped-optimal control algorithm is employed. An active control strategy, shown in previous researches to perform well at controlling the benchmark bridge when uniform earthquake motion was assumed, is also used in this study to control this benchmark bridge with consideration of multiple-support excitations. The performance of active control system is compared to that of the presented semi-active control strategy. Because the MR fluid damper is a controllable energy- dissipation device that cannot add mechanical energy to the structural system, the proposed control strategy is fail-safe in that bounded-input, bounded-output stability of the controlled structure is guaranteed. The numerical results demonstrated that the performance of the presented control design is nearly the same as that of the active control system; and that the MR dampers can effectively be used to control seismically excited cable-stayed bridges with multiple-support excitations. 相似文献
2.
To effectively reduce the damage to people and devices in civil defense engineering subjected to blast shock, a blast shock isolation system with magnetorheological fluid dampers (MRFD) is proposed. MRFD can provide continuously adjustable Coulomb friction and has many advantages for semi-active control. Numerical simulation of this isolation system is finished using Matlab simulink toolbox. General semi-active control algorithms are consided based on instantaneous optimal active control algorithm. And the results indicate that the shock isolation system can work efficiently, decreasing about 93% of the peak acceleration of the isolation floor. 相似文献
3.
设计了一种半主动力跟踪PI控制器，对由磁流液(MR)阻尼器作为悬架阻尼器的汽车模型进行控制分析．MR阻尼器的2种不同模型在闭环的汽车悬架控制系统模型中得到了应用．2种模型是基于均值阻尼力对速度(f-v)特性的均值F-v模型，和描述阻尼力非光滑滞环和饱和特性的滞环f-v模型．汽车模型用来研究力跟踪PI控制算法和MR阻尼器对车辆的振动抑制性能．仿真分析还指出了MR阻尼器的非线性，特别是滞环特性对汽车悬架系统的性能影响．结果表明所提出的控制方法对由MR阻尼器驱动的汽车悬架系统能产生很好的减振效果，不仅体现在对悬架弹簧支撑车厢的共振抑制和对驾乘人员舒适性敏感频域的振动抑制，还体现在对汽车轮胎共振频率周围的振动抑制．结果还进一步说明了MR阻尼器所存在的滞环特性对汽车悬架性能的不良影响． 相似文献
4.
郑玲 《重庆大学学报(英文版)》2003,2(1)
~~under the sliding mode controller. It shows that the sliding mode controller yield almost perfect tracking to the reference model. It can be seen in Fig.6 that the acceleration of sprung mass under sliding mode controller is controlled within ?.7 m/s2. Fig.7 shows the robustness and stability of the sliding mode controller to the parameter variations of the system to be controlled, in this case, a relative decrease of 10 % in the sprung mass and a relative increase of 15 % in the stiffness o… 相似文献
5.
A new sliding mode controller for semi-active suspension system with magnetorheological (MR) damper is presented in this paper. In the proposed sliding mode controller, a semi-active suspension based on the skyhook damper system is chosen as the reference model to be followed, and the control law is so determined that the asymptotically stable error dynamics occurs between the controlled state and the reference model state. Numerical simulations are carried out to study the performance of the new sliding mode controller. The results show that the proposed controller yields almost perfect tracking to the reference model and has a high robustness against model parameter uncertainties and disturbances. 相似文献
6.
程怡 《福建工程学院学报》2018,(4):320-325
以某跨径为110 m的独塔异形斜拉桥为工程背景,通过非线性有限元分析对斜拉桥在强震作用下的地震响应特性及减震措施进行了研究,得出如下结论:相比Lander-amboy波,卓越周期与桥梁固有周期较为接近的Cerro Prieto波能够引起结构较大的地震响应。行波效应能够显著增大工程背景斜拉桥的地震响应,且随着视波速的增大,桥梁的加速度响应明显增大。阻尼系数25 000 kN·s/m为工程背景斜拉桥的最优粘滞阻尼器设计参数,且在塔梁连接处安装该参数粘滞阻尼器后,斜拉桥减震效果显著,尤其能明显减小结构的位移响应。 相似文献
7.
研究目的：通过非线性动力有限元分析,模拟多塔斜拉桥在多点激励下的地震响应以及揭爪其在强震下的倒塌破坏模式。创新要点：解决了多塔斜拉桥的非线性动力数值模拟技术,并首次模拟了多塔斜拉桥在强震下的破坏模式。研究方法：首先采用隐式的Newmark-β法求解多点地震激励下的非线性动力方程（图3）,随后采用显式的中心差分格式对强震作用下桥梁的倒塌破坏过程进行数值仿真（图4）。重要结论：1．单主梁模犁的数值结果可以很好地反映地震模拟振动台试验的地震响应结果;2．在加速度峰值为4．0m／s2的E1。Centro波时,多塔斜拉桥模型只出现了中塔支座的破坏;3．在加速度峰值为4．0m／s2的江心波时,多塔斜拉桥模型先后出现了支序破坏、拉索与塔的连接破坏以及中塔上塔柱段的单元失效。 相似文献
8.
研究目的：创新要点：为多塔斜拉桥在一致激励和非一致激励下地震响应的研究提供地震模拟振动台全桥试验方法,并有助于加强多塔斜拉桥抗震性能和抗震设计的认识。1．建立了地震模拟振动台多台阵试验方法,并首次将其应用于多塔斜拉桥全桥比例缩尺模型的地震响应分析之中;2．通过地震模拟振动台试验,揭示了多塔斜拉桥在多点一致激励和多点非一致激励的地震响应特性并提出了多塔斜拉桥在强震下的破坏模式。研究方法：1．基于动力相似理论,设计与制作了多塔斜拉桥的全桥比例缩尺模型（图2）;2．利用地震模拟振动台多台阵试验,根据在不同地震波作用下和考虑行波效应后多塔斜拉桥模型的主梁和主塔响应,分析了多塔斜拉桥在多点一致激励和多点非一致激励的地震响应特性（图5～图8）;3．根据在地震波不同强度作用下多塔斜拉桥模型的主梁和主塔响虚,分析了多塔斜拉桥在强震下的破坏模式和地震响应（图9）。重要结论：1．江心波作用下该多塔斜拉桥的地震响应大于其他三种地震波;2．多塔斜拉桥在抗震设计时需要考虑行波效应的影响;3．在El-Centro波的加速度峰值高达4．0m／s^2时,多塔斜拉桥模型出现了支座破坏。 相似文献
9.
The magnetorheological (MR) fluid damper-based semiactive control systems have received considerable attention for protecting structures against natural hazards such as strong earthquakes and high winds. In this paper, a novel modal controller using wavelet packet transform (WPT) is proposed for the vibration control of distributed structures. In the proposed control system, the WPT method is utilized to decompose the acceleration measurement and select the modes containing most of the WPT energy component as the dominant modes. Then, a modal controller is designed to control the dominant modes and the optimal active control force is solved. Finally, Clipped-optimal con- trol law is adopted to determine the voltage applied to each MR damper. A Kalman-filter observer, which estimates the full controlled modal states from local accelerometer feedbacks, is designed for rendering the controller to be more applicable to distributed structures with a large number of degrees of freedom. A numerical example of a stadium roof structure installed with MRF-04K damper is presented. The effectiveness of the controller is evaluated under both Tianjin and El Centro earthquake excitations. The superior performance and adaptability of the controller for versatile loading conditions are demonstrated through the comparison with traditional truncated modal controller. 相似文献
10.
对土木工程结构减震控制方法进行了综述.阐述了结构控制发展历程、结构控制原理、结构控制方法(被动控制、主动控制、半主动控制、混合控制和智能控制)与应用研究概况,指出结构控制中存在的问题及解决办法,介绍了结构控制研究的热点benchmark问题. 相似文献
11.
12.
On the basis of analyzing the system constitution of vehicle semi-active suspension,a 4-DOF(degree of freedom)dynamic model is established.A tunable fuzzy logic controller is designed by using without quantification method and taking into account the uncertainty,nonlinearity and complexity of parameters for a vehicle suspension system.Simulation to test the performance of this controller is performed under random excitations and definite disturbances of a C grade road,and the effects of time delay and changes of system parameters on the vehicle suspension system are researched.The numerical simulation shows that the performance of the designed tunable fuzzy logic controller is effective,stable and reliable. 相似文献
13.
为了克服单相有源电力滤波器的非线性特性,在基于数据的基础上,由极限学习机建立有源滤波器非线性系统的内模和逆模,实现基于极限学习机的内模控制.根据内模控制系统稳态误差,评估内模控制系统的性能,并将极限学习机的内模控制系统与神经网络、核岭回归、支持向量机等方法进行比较分析.试验仿真表明,基于极限学习机的内模控制系统具有系统稳态误差小、鲁棒性强等特点. 相似文献
14.
This paper presents a nonlinear dynamic model for simulation and analysis of a kind of parametrically excited vibration of
stay cable caused by support motion in cable-stayed bridges. The sag, inclination angle of the stay cable are considered in
the model, based on which, the oscillation mechanism and dynamic response characteristics of this kind of vibration are analyzed
through numerical, calculation. It is noted that parametrically excited oscillation of a stay cable with certain, sag, inclination
angle and initial static tension force may occur in cable-stayed bridges due to deck vibration under the condition that the
natural frequency of a cable approaches to about half of the, first model frequency of the bridge deck system. A new vibration
control system installed on the cable anchorage is proposed as a possible damping system to suppress, the cable parametric
oscillation. The numerical calculation results showed that with the use of this damping system, the cable oscillation due
to the vibration of the deck and/or towers will be considerably reduced.
Project supported by National Natural Science Foundation of China (No. 59978044) 相似文献
15.
Hao WANG Tian-you TAO Huai-yu CHENG Ai-qun LI 《浙江大学学报(A卷英文版)》2014,(10):798-812
研究目的：为超大跨度斜拉桥抗风设计与抖振控制提供参考。研究方法：基于ANSYS建立了苏通大桥三维有限元模型,并在MATLAB平台模拟了苏通大桥三维脉动风场。考虑主梁断面气动自激力,进行了苏通大桥抖振时域分析。根据苏通大桥动力特性和抖振时域分析结果,重点分析了多重调谐质量阻尼器（MTMD）用于抖振控制的参数敏感性。考虑MTMD的控制效果、建造费用、施工难度及鲁棒性等因素建立了关于MTMD设计参数的目标函数,并基于一阶优化算法进行目标函数最优解的非线性搜索,据此获得了MTMD在约束条件下的最优设计参数。重要结论：1.苏通大桥侧向抖振位移主要由第一阶侧弯振型控制,竖向抖振位移主要由第一阶竖弯振型控制;2.MTMD的控制效果对设计参数的变化十分敏感,其中质量比和频带宽敏感性更强;3.MTMD的最优设计参数可以通过一阶优化算法获得,并可通过零阶优化算法对优化结果进行验证;4.采用优化后的MTMD设计参数,苏通大桥的抖振响应可以得到明显抑制,且侧向抖振控制效果更加明显。 相似文献
16.
不确定型层次分析在斜拉桥状态评估中的应用 总被引：1，自引：0，他引：1
为了确保大跨度斜拉桥的安全运营,保证桥梁的使用寿命,采用不确定型层次分析法对桥梁的状态进行评估.介绍了不确定型层次分析法的相关理论和应用对象,在众多计算区间数判断矩阵的方法中,经过对比分析选用了最优传递矩阵理论,因为其计算结果精确可靠.以哈尔滨松花江斜拉桥为背景桥,利用不确定型层次分析法建立了该桥状态评估的指标体系和评估模型,确定了评估指标的权重并通过计算得到该桥最终的状态评估值,证明了该方法的可行性与实用性.这种评估方法的应用将会为大跨度斜拉桥的养护管理提供更加科学的依据. 相似文献
17.
汽车磁流变半主动悬架的模糊控制 总被引：1，自引：0，他引：1
为带有磁流变液智能阻尼器的半主动汽车悬架系统设计了一种模糊控制器：将半主动悬架相对位移的误差及误差变化率作为模糊控制器的输入,阻尼力作为其输出,利用磁流变液智能阻尼器的阻尼力随电流变化的特性使车身的振动降到最小。仿真实验给出了最优被动悬架和模糊控制智能半主动悬架在随机路面激励情况下的响应曲线,结果表明,磁流变半主动悬架系统采用模糊控制效果较理想,其车身垂直加速度等参数变化幅度也有所降低。 相似文献
18.
Experimental Study on Magnetorheological Damper for Semi-Active Vibration Control of Civil Infrastructures 总被引：3，自引：0，他引：3
Magnetorheological (MR) fluid is a kind of smart material whose rheological properties can be rapidly varied in magnetic field. To make full use of the advantages of MR fluid to devices, a model of double-ended,shear-combined and valve-typed MR damper is designed and manufactured, and the dynamic properties under sinusoidal excitations are experimentally studied. The experiment results show that the maximum damping force of the MR damper at the full magnetic intensity reaches about 20 k while the maximum power required is less than 50W, which predicts that the MR damper will be a powerful measurement for semi-active vibration control of civil infrastructures. 相似文献
19.
鉴于矮塔斜拉桥受力性能的特殊性,引入增量动力分析（IDA）和拉丁超立方体抽样（LHS）评估该结构在地震激励下发生损伤的风险概率。首先采用LHS考虑桥梁构件材料的随机性,与事先选取的地震波相结合形成桥梁-地震动样本集合;其次在确定桥梁有限元模型主要构件损伤指标的基础上采用基于蒙特卡罗（MC）抽样的IDA进行地震易损性分析和地震风险概率评估。为验证方法的正确性和有效性,对一预应力混凝土独塔双索面矮塔斜拉桥结构模型进行地震风险概率评估,结果表明:该方法既充分考虑了材料和地震输入双重随机性又避免了繁琐的积分过程,同时也提高了工程计算的效率及精度。 相似文献
20.
CUI Yu-long LIU Hong WANG Jing-qin SUN Shu-guang 《浙江大学学报(A卷英文版)》2007,8(3):416-421
This paper first discusses the operating principle of instantaneous reactive power theory. Then, the theory is introduced into shunt active power filter and its control scheme is studied. Finally, Matlab/Simulink power system toolbox is used to simulate the system. In the simulation model, as the most common harmonic source, 3-phase thyristor bridge rectifier circuit is constructed. The simulation results before and after the shunt active filter was switched to the system corresponding to different firing angles of the thyristors are presented and analyzed, which demonstrate the practicability and reliability of the proposed shunt active filter scheme. 相似文献