Analysis of mechanical properties and defect failure of clinched joints for joining AA5052 sheets with sandwich structures

Abstract

As the simplest, most efficient, and environmentally friendly among mechanical joining methods, mechanical clinching process has been favored by industrial manufacturers increasingly. In this work, a novel investigation of the mechanical properties of the single-point butt clinched (SPBC) joints with sandwich structures formed by various forces is carried out. Further, the failure mode, fracture micromorphology, defect evolution and energy absorption during the failure process were also analyzed to investigate how the forming force affects joint performance. Based on the experimental results, it can be concluded that the SPBC joint exhibits superior performance both in terms of load-bearing capacity and safety when the forming force of joint is 45 kN, in which tensile-shear strength is 1634.75 N and energy absorption is 7.33 J. When considering the presence of upper and lower mechanical interlocks, the failure mode of the SPBC joint is limited to neck fracture, and all present the characteristics of ductile fracture microscopically. The static tensile-shear strength represents the predominant determinant of the energy absorption capacity of the SPBC joint, while the effect of deformation displacement during the failure process remains marginal. This work exploits the potential of the clinching process for SPBC joints to improve the metal formability in thin-walled structures and extend the industrial joining scenarios.