Electrorheological-Fluid Dampers: Testing Modeling and Application in Vibration and Seismic Protection of Buildingsand Bridges

9300827 Makris建筑物和桥梁的地震响应可以大大改善时，额外的耗散单元（阻尼器）使用。大多数阻尼器的耗能能力是基于它们所包含的某种粘性或粘弹性流体的剪切作用。 到目前为止，它主要以被动的方式使用。 本文提出将被动控制的概念与主动控制的优点联合收割机相结合，以产生最优的、稳定的和可靠的阻尼系统。 当阻尼器内的流体用电流变流体代替时，这种组合是可行的。 电流变液在外加电场作用下，其粘度和动态剪切模量会发生急剧变化。 本研究提出：（1）在实验室中制备适合土木工程应用的稳定电流变液。（几种现有的ER流体由分散剂相中的颗粒悬浮液组成。 在长时间的非活性期之后，发生悬浮液的沉降，这导致流体ER活性的损失。 (2)建立电流变液流变行为的唯象模型，并进行实验标定。 (3)开发分析和数值工具，根据材料行为的本构模型预测阻尼器响应。 这些工具将导致现实的宏观力位移模型的阻尼器单元，并可能设计的最佳阻尼器的几何形状。 (4)扩展和开发算法，通过修改ER的物理和机械特性来主动控制结构响应 h）的 0* 0*0 流体阻尼器的线性粘弹性和非线性粘塑性行为。 (5)通过简单模型结构的振动台试验，对所建立的模型和算法进行了验证。 ***

9300827 Makris Seismic response of buildings and bridges can be substantially improved when additional dissipative units (dampers) are used. The energy dissipation ability of most dampers is based on the shearing action of some viscous or viscoelastic fluid that they contain. So far, it has been used mainly in a passive manner. Herein it is proposed to combine the concepts of passive control with the benefits of active control, to produce an optimal, yet stable and reliable damping system. This combination is feasible when the fluid within the dampers is replaced with electrorheological fluid. Electrorheological (ER) fluids can quickly undergo a drastic change in their viscosity and dynamic shear modulus when an electric field is applied. In this study it is proposed: (1) To manufacture in laboratory stable electrorheological fluids, adequate for civil engineering applications. (Several of the existing ER fluids consist of particle suspensions within a dispersant phase. After long inactive periods settling of the suspension occurs which results to loss of the fluid ER activity. (2) To develop realistic phenomenological models for the rheological behavior of the developed ER fluid, which will be experimentally calibrated. (3) To develop analytical and numerical tools to predict the damper response based on the constitutive models developed for the material behavior. These tools will lead to realistic macroscopic force displacement models for the damper unit, and possibly to the design of optimal damper geometries. (4) To extend and develop algorithms that will actively control the structural response by modifying the physical and mechanical properties of ER h) 0*0*0* fluid dampers for linear viscoelastic and nonlinear viscoplastic behavior. (5) To experimentally verify the developed models and algorithms with shake table tests on simple model structures. ***