Effect of joint design on the failure behaviour of three-stack-up austenitic stainless steel resistance spot welds

Tensile shear tests were carried out on three-stack-up austenitic stainless steel resistance spot welds having four types of joint design. Mechanics-based criteria were applied to reveal the difference in the stress state at the microstructural level. Optical microscopy and scanning electron microscopy showed evidence of the different stress states for different joint designs. Nugget rotation generated combined tensile/shear stress at the microstructural level. The peak load and the energy absorption of the joints reduced with the growth of the normal component of the global loads. Joints for which both interfaces bear the load were more prone to failure in pull-out mode.