Modal Analysis and Local Stiffness Optimization for Body-in-white of Car

Abstract

Using preprocessing software Hypermesh and FEA software MSC. Nastran, the detailed finite element model of car body-in-white (BIW) was established based on the theory of finite element. Finite element modal analysis and experimental modal analysis were conducted to get the modal parameters of BIW including natural frequencies and corresponding mode shapes respectively. With comparison of the result of the simulation with that of test, the validity of the FEA model was verified. From the view of vibration and strength, the impact of internal and external incentives on the BIW was analyzed. According to strain mode local characteristics, a new method to determine the position where the maximum elastic deformation takes place by using the strain energy distribution of the vibration modes of different orders was therefore proposed. The method can be used to improve the local rigidity of BIW. The result shows that this method is reasonable and practical for the car body design.