Fatigue Analysis And Research Of The Body-in-White

Fatigue analysis for vehicle is one of the steps during development process. The advantage of leveraging computer aided engineering (CAE) is to drive the design to more mature levels by interactions for ahead of hardware or prototype's availability. Potential risk and failure modes are predicted and prevented much earlier in the development stage. The virtual development lays the foundation for shortening development time and reducing cost.Fatigue performance of a minibus's body-in-white(BIW) is analyzed based on finite element method(FEM),multi-body dynamics(MBD) and fatigue theory. The finite element model of BIW is established, the stiffness is analyzed by FEM and test. It is found that the results of experiments are in good agreement with that of finite element analyses. It is proven that the finite element model can be used for further analysis. The vertical displacement of the C-level road is built by Partial Wave Adding model and compared with national standards. The correctness of simulation result is confirmed by PSD analysis of random signal and nation standards, and that can be used as excitation signals for vehicle dynamics simulation. Seven degree-of-freedom (7DOF) dynamic model is developed. Multi-body dynamic model is employed to simulate the vehicle movement state under C-level load excitation, while the load history at the connection between body and suspension is recorded. The stress influence coefficients are performed based on inertia relief method, the stress histories developed within dynamically load is calculated using the quasi-static stress analysis method. The fatigue performance of body is analyzed with S-N method, the life of BIW structure of Minibus running on C-level road is estimated, which can provide significant basis and method for test and optimizing the design.