Experimental and numerical investigation on incremental laser shock clinching for joining three sheets of copper/aluminum/stainless steel

Abstract

A novel method to make a round end rectangular joint whose total length is much larger than the diameter of the laser spot, named as incremental laser shock clinching, was proposed in this paper. Experimental and numerical investigation was conducted to verify the feasibility for joining three sheets of copper/aluminum/stainless steel. The transverse section and the appearance of the joint were explored to determine the spacer height and the forming strategy. The shape evolution of interlock was discussed by observing sectional images. To describe the material flow characteristics in the forming process, a series of typical points were traced. The mechanical properties of the joints relating to the load directions and clamping ways were studied by tensile shear tests. The results show that fine joints with smooth surface morphology and uniform thickness can be obtained under the larger spacer height and multi-passformingstrategy. Simulated results agree well with the experimental results, which implies that the finite element model can be effectively used to analyze the process. During deformation, most material flows along the transverse direction to form undercuts, meanwhile flows slightly towards the laser spot moving direction. What’s more, the maximum load in the perpendicular shear test is larger than that in the parallel shear test. Two failure modes are observed when the copper foil and pre-slotted sheet are clamped on one side and only one failure mode is found when the copper foil is clamped alone.