The Fatiguean Alysis Of Automobile Body Structure Based On Rigid-flexible Coupled Method

As a key bearing structure of the vehicle, the strength and fatigue performance of the body are important indexes to ensure the reliability and durability of the vehicle. Then the traditional methods of performance analysis on body structure mainly contain static strength analysis and reliability test. The body structure design which is based on static strength tends to make the fatigue life of the structure infinite. At the same time, the reliability test has longer cycle, high cost and is difficult to quickly identify the fatigue performance of the structure. Therefore, the virtual durability test technology will provide a fast and effective method for the evaluation and design of the body structure fatigue performance.As an engineering research project, this study will combine the finite element analysis technology, virtual prototype modeling technology, virtual test technology and fatigue life prediction technology together to conduct the fatigue analysis of the body structure and then conduct the test of experimental verification and structure optimization. The method which conducted the durability test and fatigue analysis of the body structure based on the virtual technology can quickly and effectively evaluate the fatigue performance of the structure, shorten the development cycle, reduce the cost and improve the product quality. Consequently, this study has good theoretical guidance and project application significance. This paper took certain business model as the object of study, firstly built the finite element model and the flexible model of the body structure, and then established the rigid-flexible coupling dynamic model of the vehicle by virtual prototype modeling technology. Next, the durability virtual road was built and used as the excitation of the vehicle virtual test, and then obtained the dynamic boundary loads of the body. Finally, predicted the fatigue life of the fatigue weak area of the body structure according to the static stacking calculation method and focused on the analysis and optimization of the rear swing arm mounting base which has cracks during the durability test. As a summary, this paper established a basic process for fatigue life prediction of the body structure based on durability virtual test.