建筑结构被动控制发展动态

本文对建筑结构被动控制发展过程和动态者综述,主要介绍了建筑结构被动控制中常用的金属屈服阻尼器、摩擦阻尼器、可调质量阻尼器、粘弹性阻尼器、可调流体阻尼顺和粘性液体阻尼器。     

带支撑Maxwell阻尼器耗能隔震结构的随机风振响应分析

对设置带支撑Maxwell阻尼器的高层耗能隔震结构的随机风振响应进行了研究。建立结构运动方程,基于传递函数法及随机振动理论,获得结构基于Davenport谱激励下位移和阻尼器受力响应方差,并将其分解为系列标准振子的线性组合,得到结构随机风振响应的解析表达式、阻尼器受力的随机响应、等效风荷载取值,从而建立了带支撑Maxwell阻尼器高层耗能隔震结构的随机风振响应解析分析方法。算例分析表明:支撑刚度对阻尼器的减震效果有着较大的影响,以上部结构风振位移响应为例,阻尼器的支撑刚度为1倍隔震层刚度比支撑刚度为0.001倍隔震层刚度的位移响应减小了30%左右。所获得的解析解对耗能隔震结构的设计和阻尼器的参数优化设计具有重要的意义。     

粘弹性阻尼器动力设计及其应用的实验研究

本文提出一种圆柱式剪切型粘弹性阻尼器，给出其具有结构阻尼特性的单自由度动力学系统模型，用正弦扫频实验技术实现了对阻尼器动力学特性的测量。通过实验，研究了粘弹性材料动态特性与阻尼器动力学特性的关系，并给出这种关系的数学表示，给出了这类阻尼器的设计方法和基本公式。实验结果表明，应用这种阻尼器可有效控制桁架结构的振动，实现对结构的阻尼控制。     

阻尼耗能减振框架结构地震作用振动方程求解及地震反应分析Calculation of vibration equation and analysis of seismic response for damping energy dissipation frame structure

研究了设置耗能阻尼器框架的地震作用振动方程求解及该结构的地震反应。框架结构设置耗能阻尼器后,振动方程的阻尼矩阵不再对振型具有正交性,本文对该振动方程给出了状态方程直接积分法,并与传统强制解耦法进行了比较分析,结果表明强制解耦法对结构第一阶振动反应求解偏差较小,而对于高阶振动反应差别较大,并且强制解耦法高估了阻尼器的减震效果。继而采用状态方程直接积分法对设置有粘滞阻尼器的框架结构进行了地震反应分析,探讨了阻尼器位置对框架结构地震反应的影响,结果表明设置有阻尼器的楼层减振效果明显,未设置阻尼器的楼层减振效果差别较大,甚至有可能出现楼层层间侧移增大的现象,由此提出耗能阻尼器应在结构中合理设置。     

阻尼耗能减振框架结构地震作用振动方程求解及地震反应分析

研究了设置耗能阻尼器框架的地震作用振动方程求解及该结构的地震反应。框架结构设置耗能阻尼器后,振动方程的阻尼矩阵不再对振型具有正交性,本文对该振动方程给出了状态方程直接积分法,并与传统强制解耦法进行了比较分析,结果表明强制解耦法对结构第一阶振动反应求解偏差较小,而对于高阶振动反应差别较大,并且强制解耦法高估了阻尼器的减震效果。继而采用状态方程直接积分法对设置有粘滞阻尼器的框架结构进行了地震反应分析,探讨了阻尼器位置对框架结构地震反应的影响,结果表明设置有阻尼器的楼层减振效果明显,未设置阻尼器的楼层减振效果差别较大,甚至有可能出现楼层层间侧移增大的现象,由此提出耗能阻尼器应在结构中合理设置。     

端部控制磁流变液阻尼器实验研究

以提高磁流变液阻尼器控制性能为目的,分析了活塞式磁流变液阻尼器结构特点,并提出了端部阻尼器结构;通过实验研究明确了磁流变液流经圆形截面和矩形截面的力学特性,总结了磁流变液流经不同类型和尺寸的小孔的粘性阻尼力特性和磁场作用时的磁场效应,并得出了提高端部阻尼器控制性能的方法和措施。设计出控制性能较好的矩形截面孔的端部控制磁流变液阻尼器。给出阻尼器最大阻尼力和可控比与线圈磁场强度关系。     

带支撑黏弹性阻尼器框架减震性能分析

对带有支撑黏弹性阻尼器耗能框架结构振动方程进行傅里叶变换,求解该振动方程的频域解,再通过傅里叶逆变换得出该方程的时域解,由此研究了阻尼器的支撑系数ψ、松弛时间系数η对结构地震响应的影响,分析了带支撑黏弹性阻尼器在结构各楼层均匀布置时结构的地震作用及结构各振型的底部剪力。结果表明:支撑系数ψ超过一定数值时,阻尼器支撑对结构的地震反应影响很小;框架结构中带支撑的黏弹性阻尼器宜合理控制松弛时间系数η,使其不大于0.5。     

基于放大式节点阻尼器的框架结构抗震性能研究

针对普通节点阻尼器在层间位移角较小时无法充分发挥阻尼器性能的问题,基于杠杆原理提出一种新型位移放大式节点阻尼器。首先介绍阻尼器的基本构造、工作原理并建立数值模型;然后建立含阻尼器的多尺度框架模型,开展结构静、动力弹塑性分析,探讨位移放大阻尼器与无放大阻尼器对框架结构抗震性能的影响。研究结果表明:放大式节点阻尼器耗能能力为无放大阻尼器的5.7倍;在多遇及罕遇地震作用下,相比布置无放大阻尼器的框架结构,布置放大式节点阻尼器的框架结构基底剪力响应分别减少13%、6%,层间位移角分别减少13%、11%,有效提升了结构的抗震性能。     

高效耗能摩擦阻尼钢筋混凝土框架结构减震性能分析

研究了高效耗能摩擦阻尼器的减震机理。利用力学原理，分析了地震作用下高效耗能摩擦阻尼器的摩擦阻尼力放大系数变化规律，推导了设置高效耗能摩擦阻尼器结构的等效阻尼比计算公式。在此基础上，对分别设置传统摩擦阻尼器和高效耗能摩擦阻尼器的框架结构进行了地震反应分析，结果表明，高效耗能摩擦阻尼器通过将较小的摩擦阻尼力放大可以显著降低结构地震反应，减震效果良好；利用本文给出的等效阻尼比分析得出结构顶层位移反应幅值，与阻尼等效前相应值误差不超过10%。     

MR阻尼器的半主动控制研究

MR阻尼器能提供可以调节的阻尼力,适合用作减少结构地震响应的半主动控制器。本文对MR阻尼器的半主动控制进行研究,提出了状态跳跃算法,根据结构响应的大小实现MR阻尼器的状态切换,使结构响应得到有效的控制。这种控制策略简便,不需要在线计算,便于实施。由于速度响应直接影响MR阻尼器的阻尼力,建议用速度响应作为MR阻尼器进行状态切换的变量。文中给出了两个算例,进行了计算分析和比较,说明了状态跳跃控制算法的特点。     

An analytical approach to optimally design of electrorheological fluid damper for vehicle suspension system

This work develops an analytical approach to optimally design electrorheological (ER) dampers, especially for vehicle suspension system. The optimal design considers both stability and ride comfort of vehicle application. After describing the schematic configuration and operating principle of the ER damper, a quasi-static model is derived on the basis of Bingham rheological laws of ER fluid. Based on the quasi-static model, the optimization problem for the ER damper is built. The optimization problem is to find optimal value of significant geometric dimensions of the ER damper, such as the ER duct length, ER duct radius, ER duct gap and the piston shaft radius, that maximize damping force of the ER damper. The two constrained conditions for the optimization problem are: the damping ratio of the damper in the absence of the electric field is small enough for ride comfort and the buckling condition of the piston shaft is satisfied. From the proposed optimal design, the optimal solution of the ER damper constrained in a specific volume is obtained. In order to evaluate performance of the optimized ER damper, simulation result of a quarter-car suspension system installed with the optimized ER damper is presented and compared with that of the non-optimized ER damper suspension system. Finally, the optimal results of the ER damper constrained in different volumes are obtained and presented in order to figure out the effect of constrained volume on the optimal design of ER damper.     

Design and test of a friction damper to reduce engine vibrations on a space launcher

Space launchers are submitted to complex vibration environments and this can impact the payload it is carrying. Ensuring the protection of the payload therefore requires the addition of a secondary system. In this paper, a rapid design method for the dimensioning of a friction damper is developed, based on the equivalent energy dissipation with that of a viscous damper. A friction damper is designed and a prototype is built. The friction damper is first characterised alone and it is then mounted inside a scale model of a launcher last stage. The friction damper is adequately modelled by a spring in series with a friction element. The damper prototype proves to efficiently damp the rocket engine vibrations, and the design method used for dimensioning the friction damper gives a good approximation for the optimal sliding force of the damper.     

Fluid formulae for damping changeability conceptual design of railway semi-active hydraulic dampers

Damping changeability design and evaluation is the most fundamental issue at the beginning of any new railway semi-active hydraulic damper development. Therefore, physical fluid mechanics for the calculation of basic structure and resistance parameters of the damper should be carefully studied in the conceptual phase. Fluid formulae for changeable damping performance evaluation of two commercial railway semi-active hydraulic dampers are established. Simulation results show that the damper switched by high-speed solenoid valves obtains a wide range of changeable damping coefficients, which guarantees the absorption of a wide spectrum of vibrations; however, a different low cost damper regulated with an inversely proportional relief valve, whose Force-velocity characteristics share the same rising curve, is relatively limited in damping ability. In order to overcome the drawback of the latter one with no obvious cost increase, a new semi-active hydraulic damper which is regulated by a simple proportional throttle valve is proposed. Continued fluid formulation and simulation suggests that the damper can change its damping force rising curves or “effective” damping coefficients continuously, within a considerably wide range. Thus, fluid formulae explicitly established in this study are of significance in the damping changeability conceptual design, further refinement and control design for the three semi-active hydraulic dampers. The proposed new damper, which has both a simple configuration and an easy-to-control ability, might be feasible for industry applications.     

Design and mechanical characteristics analysis of a new viscous damper for piping system

In this paper, the design of a new viscous damper is presented and its mechanical characteristics are investigated experimentally. The motion equation of a system consisting of a drop machine and the damper is set up. By numerically simulating this equation, the curve of the damper cavity generatrix is obtained on the assumption that the resisting force is constant. Then the new damper with big capacity and high-energy dissipation rate is designed. Drop tests using this damper and a Pro225-damper bought in the market are performed, respectively. On one hand, the experimental resisting forces of the new damper approximate constants, which illustrates that the simulation is viable. On the other hand, some advantages of the new damper over the Pro225-damper are found.     

A new semiactive nonlinear adaptive controller for structures using MR damper: Design and experimental validation

In this study, we consider the vibration mitigation problem for a structural system using a magneto-rheological (MR) damper. For this purpose, through the use of Lyapunov-based design techniques, a nonlinear adaptive controller which can compensate the parametric uncertainties related to both the structural system and the MR damper has been constructed. To overcome effects of the unmeasurable internal dynamics of the MR damper on the controller, a filter-based design has been utilized. Experimental results performed on a six-degree-of-freedom (DOF) structure installed on a shaking table, illustrating the viability and the performance of the proposed method are also included.     

Design method for fluid viscous dampers

A basic design method of doubly acting fluid viscous dampers with double guide bars is presented. The flow of the viscoelastic fluid between two parallel plates, one of which is started suddenly and the other of which is still, is analyzed. According to this solution, the velocity and the shear stress of the fluid at the fringe of the piston are solved approximately. A mathematical model of viscous dampers is derived, and the shock test is carried out. From experimental results, the parameters of the mathematical model are determined. Consequently, a semi-empirical design equation is obtained. Applying this equation to a certain practical damper, the damping material is chosen and the physical dimensions of the damper are determined. Shock tests using this damper are performed. Theoretical results are in good agreement with experimental results, which validates the reliability of the calculated physical dimensions of the specimen damper and the validity of the basic design equation. An erratum to this article can be found at     

Nonlinear modeling and experimental characterization of hydraulic dampers: effects of shim stack and orifice parameters on damper performance

A nonlinear model of monotube hydraulic dampers is presented with an emphasis on the shim stack properties and their effects on the overall damper performance. There has been no published detailed analysis of the effects of shim stack design in a hydraulic damper to date. Other damper models have used simplifying assumptions for the shim stack deflection and effects of the shim stack have not been completely studied. Various parameters affecting the nonlinear characteristics of monotube dampers such as the hysteresis region are studied. The model presented in this paper can be used for design purposes and helps in developing controllable valvings based on shim stacks. It can also be used to design controllable bypasses in hydraulic dampers. The mathematical model is validated by comparison against experimental test results carried out on an OHLINS CCJ 23/8 monotube damper, in CVeSS test facilities.     

SMA阻尼器的阻尼特性分析及器件设计方法

提出了SMA中心引线型阻尼器的力学计算模型，以Brinson本构模型为理论依据建立了阻尼器的阻尼特性分析理论及器件设计方法；利用MATLAB编制的仿真软件进行了实例仿真。结果表明SMA阻尼器具有明显的阻尼特性，加上其耐久性和免维护性，适合用于土木工程的结构振动被动控制。     

NEURAL NETWORK MODEL OF MAGNETORHEOLOGICAL DAMPER FOR VIBRATION ISOLATION PLATFORM OF WHOLE-SPACECRAFT

为改善星箭界面振动环境,设计六杆隔振平台,采用磁流变阻尼器作为半主动控制元件,替代原有锥壳过渡支架.对整星隔振平台用磁流变阻尼器进行性能测试,得到反映磁流变阻尼器阻尼特性的实验数据.建立具有两个隐含层的反向传播神经网络对阻尼器进行建模,用于预测磁流变阻尼器阻尼特性以及控制系统设计.提出一种串行算法优化网络结构、权值和阈值,保证网络具有较好的泛化能力和稳定性.仿真结果表明,与参数化模型相比,提出的神经网络模型具有较小的训练误差和较强的泛化能力,能够很好地预测阻尼器的阻尼特性.     

颗粒阻尼在航天器减振中的应用与前景

振动抑制是航天器结构设计关心的主要问题之一。本文介绍了一种新型的颗粒阻尼技术,分析了颗粒阻尼器的背景设计难点、减振原理及其影响因素,给出了几个应用实例,对其国内外应用研究现状进行了总结。针对颗粒阻尼器的基本设计原则可以认为：颗粒阻尼器在航天器的蜂窝夹层结构中具有天然的安装优势,而其不受环境限制的特点有望为航天器结构极端工况下的部／组件减振提供一条可行的路径。