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

9300827 Makris当使用额外的耗散单元（阻尼器）时，建筑物和桥梁的地震反应可以大大改善。大多数阻尼器的能量耗散能力是基于它们所含的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。在此，提出将被动控制的概念与主动控制的优点相结合，以产生一个最优、稳定和可靠的阻尼系统。当用电流变液代替阻尼器内的流体时，这种组合是可行的。当施加电场时，电流变（ER）流体的粘度和动态剪切模量会迅速发生剧烈变化。在本研究中提出：(1)在实验室中制造适合土木工程应用的稳定电流变流体。(现有的几种ER流体由分散剂相中的颗粒悬浮液组成。经过长时间的不活跃期后，悬浮液发生沉淀，导致流体内质网活性的丧失。(2)为所开发的ER流体的流变行为建立真实的现象学模型，并将进行实验校准。(3)开发基于材料性能本构模型的分析和数值工具来预测阻尼器响应。这些工具将导致阻尼器单元的现实宏观力位移模型，并可能设计最佳的阻尼器几何形状。(4)扩展和开发算法，通过修改ER h) 0*0*0*流体阻尼器的线性粘弹性和非线性粘塑性行为的物理和机械性能来主动控制结构响应。(5)通过简单模型结构的振动台试验验证了所建立的模型和算法。＊＊＊

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. ***