Structural Finite Element Analysis And Fatigue Life Estimation Of A Body-in-white

In the process of automobile product research and development, the strength, stiffness and lifetime are the important indexes to evaluate the body-in-white. Analyze the strength, stiffness and lifetime of body-in-white by finite element method can shorten the development process of the body-in-white and reduce the cost of research and development, which has important engineering significance.This paper takes the body-in-white structure of a certain type as the research object and establishes the finite element model of the body-in-white by using the finite element pre-processing software HYPERMESH, which included the the extraction of the surface, generation of finite element mesh, the definition of spot weld, and the definition of material properties. Subsequently, this paper carried out the analysis of the free modal of the body-in-white structure by using ABAQUS, and got the low-order modal and natural frequency, which shows that the natural frequency of the body structure gets rid of the engine idling frequency and the road excitation frequency. In addtion, this paper analyzed the influence of front and rear windows for BIW modal and natural frequency.Then, this paper carried out the analysis of torsion stiffness, bending stiffness and static strength of the body-in-white, which shows that the strength and the stiffness of the body-in-white structure have met the design requirements.Finally, this paper carried out the analysis of the stress response of the body and spot weld when mounting points are respectively loaded unit excitation by using inertia relief. In the fatigue analysis software nCode, combined with the stress response of the body, body material S-N curve estimated with UTS and the load spectrum provided by automaker,we calculate the lifetime of body and spot weld, which shows that the fatigue characteristics of the body and spotweld have met the design requirements.This paper is of valuable reference for the design of automotive products, and has important practical significance.