Dynamic Modal Reanalysis Using Flexibility Disassembly Perturbation Method

In structural optimization design and reliability analysis, it is necessary to repeatedly modify the structure and calculate the corresponding vibration modal parameters. It will require significant computational costs if a complete analysis is used to calculate the vibration modes of each modified structure. In order to improve computational efficiency, this work develops a dynamic modal reanalysis method based on flexibility disassembly perturbation, which utilizes the modal data of the original structure to quickly calculate the modal parameters of the modified structure. The core idea of the proposed method is to use the flexibility matrix decomposition formula to quickly calculate the flexibility matrix after each modification of the structure and then obtain a high-precision reduced eigenvalue problem for solving the vibration modes of the modified structure. Three numerical examples are used to validate the proposed modal reanalysis method. It has been shown that the proposed method has higher computational accuracy and efficiency than the existing modal reanalysis method, especially for high-rank and large modification scenarios.