Experimental investigation of joining aluminum alloy sheets by stepped mechanical clinching

Abstract

Recently, increasing attention has been paid to sheet joining process for building lightweight structures. Clinching technology is an energy-saving and cost-efficient green joining method. The main factor affecting the development of conventional clinching using round punch is the unsatisfactory joint strength. To improve the mechanical properties of clinched joints, the tools and process parameters of the clinching process need to be optimized. In the study, the influence of forming forces on joining quality of clinched joints using a stepped punch was investigated using experimental methods. The geometrical parameter, failure mode, mechanical characteristic and energy absorption were analyzed in detail. From comparing the clinched joints created with a round punch, it can be concluded that the usage of stepped punch is meaningful to create joints with higher neck thickness. At the same forming force, the maximum increment in tensile and shear strength of the joints created by the stepped punch was 26.1% and 59.2%, respectively.