Investigation of Spot Weld Behavior Using Detailed Modeling Technique

The development of suitable and robust simplified spot weld models for full vehicle crash simulation meets one of the major demands of the development process regarding efficient and appropriate full car crash models. Normally a high number of experiments are required to derive and validate accordant material and failure parameters for each material and gage combinations. Concerning systematical investigations, the effort for manufacturing and testing can increase immoderately. In this paper, we describe a method to reduce the effort of characterizing the joint failure by using a highly detailed simulation model. Different loading conditions and geometrical aspects can be analyzed by using this model in combination with the Gurson’s material model as an appropriate visco-plastic material model which includes already a damage formulation. Especially the experimental investigation of strain rate effects at higher velocities of joints is quite sophisticated due to dynamic effects of the test arrangement – the magnitudes are often overlaid by oscillations. Using the simulation to evaluate the behavior of a spot weld allows to study and predict the strain rate effect for higher velocities. As a second point, we use the detailed model for a systematic analysis to determine the effect of the sheet thickness with respect to the failure parameters. The influence of imperfections which occurs due to the production process can be eliminated, so that a self-contained approach can be obtained.