Passive Vibration Control by Solid Free-Form Structural Optimization

该研究项目的重点是开发一种创新的被动振动抑制和控制技术。提出了一种无实体-无实体结构优化设计方法。在这种设计方法中，结构被定义为微观结构元素的空间排列。结构设计从一个指定的设计域开始，作为每个可以想象的设计空间的联合，这些设计空间可以拥有材料而不违反任何几何和载荷约束。然后将设计域划分为许多小的设计单元。每个设计单元都被建模为具有微几何穿孔的“复合”材料。通过改变定义微几何结构的参数，结构的拓扑和形状被有效地表示，并可以在研究项目中获得所需的结构动态特性。研究了两种主要的被动振动抑制技术：（i）特征结构配置，和（ii）频率响应函数成形。 第一种方法的本质是根据一组所需的模态特性来推导结构的响应，而第二种方法的目的是控制结构在某些临界点和通过感兴趣的带宽的整体响应特性。 所提出的方法进行了验证，通过使用比例模型在实验测试。这项研究的结果导致了航空航天和汽车应用的被动振动控制的鲁棒设计技术的发展，以及一种新的结构设计工具，用于大幅度提高轻量化工程结构的性能。

This research project focuses on the development of an innovative passive techniques for vibration suppression and control. A design technique of solid free-free structural optimization is formulated. In this design methodology, a structure is defined as a spatial arrangement of micro- structural elements. The structural design starts with a specified design domain as a union of every conceivable design space that can possess materials without violating any geometric and loading constraints. Then the design domain is divided into many small design cells. Each of the design cells is modeled as a `composite` material with micro- geometry perforations. By changing the parameters defining the micro-geometric structures, the topology and shape of the structure is represented effectively and desired structural dynamic characteristics can be obtained during the research project. Two major passive vibration suppression techniques are investigated:(i) eigenstructure assignment, and (ii) frequency response function shaping. The essence of the first approach is to derive the response of a structure in terms of a set of desired modal properties, whereas the second approach aims at controlling the overall response characteristics of the structure at certain critical points and through a bandwidth of interest. The proposed approaches are validated by using scaled models in experimental testing. The results of this research lead to the development of robust design techniques of passive vibration control for aerospace and automotive applications, and a new structural design tool for substantial performance improvement in lightweight engineering structures.