Passive Vibration Control by Solid Free-Form Structural Optimization

本研究项目致力于开发一种创新的被动减振与控制技术。提出了一种固体自由-自由结构优化设计方法。在这种设计方法中，结构被定义为微结构元素的空间布置。结构设计从指定的设计领域开始，作为每个可以想象的设计空间的联合，这些设计空间可以在不违反任何几何和载荷约束的情况下拥有材料。然后将设计领域划分为多个小的设计单元。每个设计单元都被建模为具有微几何穿孔的复合材料。通过改变定义微观几何结构的参数，有效地表达了结构的拓扑和形状，在研究过程中可以获得所需的结构动力特性。研究了两种主要的被动减振技术：(I)特征结构配置和(Ii)频率响应函数整形。第一种方法的本质是根据一组期望的模态特性来推导结构的响应，而第二种方法的目的是通过感兴趣的带宽在某些临界点控制结构的整体响应特性。利用缩尺模型进行了实验测试，验证了方法的有效性。这一研究成果为航空航天和汽车被动振动控制稳健设计技术的发展提供了新的思路，也为轻量化工程结构的性能改进提供了一种新的结构设计工具。

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.