Study on the Finite Element Modeling of Spot Welding for Crash Analysis

Abstract

Simulation of vehicle crashes using the finite element method has made major advances in the last several years. Every major automotive company now uses CAE to perform virtual crash tests. Designers can mow quickly adjust the structural performance before performing a physical crash test. Compared to physical crash tests, the virtual simulation is less costly and faster which allows manufactures to reduce costs and vehicle development time. In order to produce more efficient and precise simulations, it is needed to adopt the dynamic property of materials and the failure modeling of resistance spot weld. The resistance spot weld in most current finite element crash models are characterized as a rigid beam at the location of the weld. The role of this rigid beam is simply to transfer the load across the welded component. The spot weld elements is design to be failed by some failure criteria which is function of axial and shear load at the rigid beam. For this reason, the calculation of the load at the rigid beam is important to predict the failure of the spot weld. In this paper, the numerical simulations are carried out to evaluate the calculation of the load at the rigid beam. The first study conducted is to examine the effect of mesh size on the load at the rigid beam. The effect of element shape on the welded components is, then, investigated. Finally, the location and the number of welded constrains is changed for the correct prediction of the load on the spot weld element. The analysis results demonstrate that the correct prediction of the load on the spot weld element is achieved by the change of the element shape on the welded component s and the location of welded constrains.