Modelling of Fracture Behaviour of Spot Welds and Adhesive Joints Under Crash Loading

It is impossible to model spot welds of a body in white in an explicit Finite Element calculation in detail because of the huge amount and the small dimensions of spot welds. Therefore simplified spot weld elements are used for a reliable and practicable modelling. The load-carrying capacities of spot welds under different loadings (lap-shear, pure tension, coach peel) are used for calibration of the damage parameters. For modelling of adhesive joints a material model based on the Fleck model was extended by the strain rate behaviour of yielding and fracture strain of the Johnson-Cook model. The model parameters were determined by simulation of tests on pure adhesive as well as on glued specimens. For crash simulation the model is calibrated to the thickness of the adhesive layer and verified by simulation component test.