Extraction of modified parts of mechanical structures based on mutual mode kinetic energy distribution for vibration reduction

摘要

Three-dimensional computer aided design technology has made remarkable advances in the manufacturing industry and has been applied to various products and scopes (e.g., motorcycle manufacturing). In addition, by adopting the finite element method (FEM), we can analyze the dynamic behaviors of products accurately. In the design stage, modal analysis using FEM calculates the natural mode shapes and frequencies of an object or structure during free vibration. To reduce the vibration or noise, natural mode shapes and the kinetic and potential energy distribution are confirmed. However, it is still difficult to design mechanical components for vibration reduction based on this information. This study presents the extraction of mechanical components for vibration reduction and a mechanical design using the tuned frequency of that component. Mechanical components, which are candidates for modified design, are extracted by mutual kinetic modal energy calculated by natural mode shapes and the mass matrix of the element. The natural frequencies of the entire structure without the candidate component and that of the candidate component alone are calculated by component modal analysis. In this case, the natural frequency of the candidate component is very close to that of the main structure, and the height of the resonance peak can be decreased. Finally, the proposed method is verified by application to a finite element model of a motorcycle.