Multi-scale mechanical modeling of Al-steel resistance spot welds

A multi-scale finite element modeling approach was developed to study the deformation and fracture behavior of Al-steel resistance spot welds. First, a micro-scale model was applied to simulate the mechanical responses of the intermetallic compound (IMC) layer having various morphologies and thicknesses under tensile and shear loading conditions. Second, the predicted tensile and shear strength of the IMC layer, that varied along the joint interface per the IMC layer morphology and thickness variation, was then introduced into 3D macro-scale models to predict the overall mechanical performance of weld coupons under coach peel, lap shear and cross-tension testing conditions. The numerical predictions agreed reasonably well with the experimental data.