The application of pre-test analysis in modal test

As a fundamental system identification experiment, modal test with an accurate result has great effects on the subsequent work, which is often restricted by many unavoidable factors. This paper discussed the method of properly selecting response and exciting points with the modal pre-test analysis based on an existing FEA modal to guide and improve the execution of modal test. A modal test was performed and analyzed with an optimized exciting and response arrangement. The modal test result can adequately express the natural characteristics of the specimen, and is more conducive to the amendment of finite element model, because the pre-test analysis derives from the FEA modal. The analytical result of the amended model is quite consistent with testing result in relation to both natural frequencies and modal shapes. The pre-test analysis can provide a convincing advice on how to design an appropriate modal test.