Experimental modal analysis and dynamic characteristic evaluation of body-in-white of some car

A new technology of modal parameter identification method called Polymax method is introduced in this paper.The experimental model of body-in-white(BIW) of some car is estab-lished,and the composition of testing system,rule for determining testing program,data acquisition and validation method of testing system are described in detail.The polymax method of software LMS Test.lab is used to carry out modal parameters identification on the collected data.Then the dynamic characteristics of BIW is evaluated based on the FRF synthesis and Modal Assurance Criterion(MAC),and the suggestion for improvement is given.Test results show that the measuring system can meet the requirement for precision,the parameter identification result is effective and reliable,enabling to provide the basis for the improvement of body-in-white structure design.