Investigation on failure mechanism of the square clinched joints with different sheet thicknesses

Abstract

An experimental investigation was carried out to probe into the effect of the thickness arrangement on the failure mechanism and mechanical behaviour of the square joint produced by square clinching tools. Failure mode, geometrical characteristics and absorbed energy of the square joint were investigated to evaluate the quality of the square joint. Full shear and button separation are two major failure types observed in failure tests. The micro morphology of different joint fractures was studied by SEM. Lap shear load and lap tensile load of the square joint were measured during failure process. From the results, the fracture of joints with various sheet thickness arrangements shows typical ductile fracture characteristics. Interlock and neck thickness of the square joints in various thickness arrangements enlarge along with the gain of the top sheet thickness. Greater mechanical load-carrying ability and absorbed energy of the square joint were observed when the thicker sheet is on the top layer. Square clinching process can achieve the joining of Al5052-H32 sheets with dissimilar thickness arrangements reliably. Thicker sheets are suitable for being placed on the top layer during the square clinching process.