Classification of Characteristic Modes for Vibration Reduction

Abstract

The finite element method (FEM) is useful for vibration analysis. However, it takes time to evaluate and reduce vibrations of large-scale structures such as automobile bodies. Especially, when treating coupled modes that consist of global and local deformations, it is necessary to reinforce respective parts that relate to each deformation. This is because applying incorrect reinforcement settings contribute to vibration increase. The purpose of this study is to classify each characteristic mode into groups depending on approaches for vibration reduction. Especially for structures such as automobile bodies, it is effective to focus on global and local deformations of each mode. Focusing on these deformations, we classified the characteristic modes of an automobile underbody structure into three groups: global modes, local modes and coupled modes. By means of the classification, we proposed effective vibration reduction approaches for each mode group. Furthermore, the effectiveness of the presented classification and vibration reduction method for each mode group is demonstrated.