Crash and durability of aluminum and mixed steel aluminum joints made by electromagnetic pulse welding
In this paper, results of the research project Failure behavior of mixed weld joints under multi-axial crash-like and cyclic loads on the example of EMPT sheet metal joints funded by the German Federal Ministry for Economic Affairs and Energy are presented and discussed. Aluminum and mixed aluminum-steel joints were prepared using electromagnetic pulse technology (EMPT) at PSTproducts GmbH (PST). Investigations on coupon samples were performed under oscillating and monotone (crash) loadings until failure. Based on the coupon tests, parameters for modelling the crash performance were derived, using both a detailed continuum model and an application driven simplified FE-model. The derived FE-modelling concept for crash behavior was validated by comparison of component tests and simulations Durability analysis of the joint specimens was performed combined with FEM analysis, applying the notch stress concept. For the notch stress concept a notch model with a reference radius of rref=0.05 mm was used for the FE-simulations. The endurable notch stresses were compared to reference S-N curves derived for conventional welded samples. The EMPT-results fit well in the scatter band of the conventional laser-welded joints. This is the verification that the notch stress concept can be successfully applied also for EMPT joints.