Modeling Viscoelastic Damping in Civil Structures

在社会结构中建模粘弹性阻尼Co-Pi的Daniel J.Inman和Eric M.Austin本研究的目标是在从基本本构关系到有限元程序的最终使用的所有层次上检查结构和结构部件中粘弹性阻尼机制的性质。许多有限元程序包含简单形式的阻尼阵，但随着土木结构性能要求的提高，更精确的阻尼阵的重要性急剧增加。粘弹性阻尼器是难以建模的量，但这些机构产生的阻尼值决定了系统在风、交通或地震荷载作用下的主要时间响应特征，因此它往往是一个关键的设计问题。有限元程序是预测振动响应的主要工具，而有限元方法中最不发达的部分是如何在动力有限元模型中考虑阻尼力。目前大多数现成的商业代码，对于执业工程师来说都是现成的，其中只包括临时的、非物理的减振。在这里。这项研究的主要目的是探索一种新的方法，将粘弹性效应纳入到标准的有限元模型中进行时间域分析。这种基于观察者的方法旨在成为近年来出现的内部变量方法的替代方法。基本概念是用来模拟时间域粘弹性行为的内部变量类似于不可测量的状态，这项研究的目的是使数十年的控制研究对这个问题产生影响。

Modeling Viscoelastic Damping in CiAl StructuresCo-Pi's Daniel J. Inman and Eric M. AustinThe goal of this research is to examine the nature of viscoelastic damping mechanisms in structures and structural components at all levels from basic constitutive relations to final usage in finite element codes. Many finite element codes incorporate simple forms of damping matrices, but as the performance demands of civil structures increases, the importance of more accurate damping matrices increases dramatically.Viscoelastic damping mechanisms are difficult quantities to model, yet the damping these mechanisms produce determines the major features of the time response of a system due to wind, traffic, or earthquake loads, and thus it is often a key design issue. Finite element codes are the chief tools for predicting vibration response, yet the least developed part of finite element methodology is how damping is incorporated into dynamic finite element models. Most current commercial codes readily available to practicing engineers include damping only in an ad hoc, nonphysical way. Here it. is proposed to investigate three promising methodologies that will allow damping to be included in finite element codes that is both physically based yet computationally compatible with existing finite element practice.The primary goal of this research is to explore a new approach to incorporating the effects of viscoelasticity into standard finite element models for time-domain analyses. This observer-based approach is intended to be an alternative to the internal-variable methods that have appeared in recent years. The basic concept is that internal variables used to model time-domain viscoelastic behavior are similar to unmeasurable states, and this research is aimed at bringing decades of controls research to bear on this problem.I