Numerical Simulations and Predictions of Spot-Weld/Weld-Bond Separation in Aluminum Closed-Hat Sections in Axial Collapse

A finite element model was used to approximate spot-weld and weld-bond separation in aluminum closed hat section components to assess existing analytical capabilities for guiding the design of aluminum structural members. The successful application of this modeling technique depended on the correct values of the joint strength in tension and shear. These strengths were obtained from single spot weld/weld bond tests, and were checked against a suitable separation criterion in the model. The model accounted for joint separation during the loading process. The validity of the technique was demonstrated on simple hat section aluminum components subjected to axial loading. In particular, spot welded and weld bonded AA5XXX components were tested. Peeling of the adhesive bonding and continuous separation of the spot welds were observed in most of these axial tests. The resulting pattern of collapse and load carrying capacity, as predicted by the dynamic non linear finite element code PAM CRASH, correlated very well with the experimental results. Consequently, the present method of analysis was deemed effective.