Numerical and Experimental Study of the Mechanical Reshaping Process for Laser Shock Clinching

This study investigates the viability of employing a mechanical reshaping method to reduce the protrusion height of laser shock-clinched joints while improving their strength. The method involves utilizing a pair of flat reshaping dies to compress the protrusion on laser shock-clinched joints made of copper foils and stainless steel sheets. Through numerical simulations and experiments, the study delves into the processes of laser shock clinching, mechanical reshaping, and failure modes of joints. Examination of the cross-sectional profiles of both clinched and reshaped joints provides insights into the influence of process parameters during mechanical reshaping. Furthermore, tensile-shear and cross-tension tests are conducted to ascertain the mechanical properties of joints. The results show that the mechanical reshaping process not only effectively reduces the protrusion height of laser shock-clinched joints but also significantly enhances their strength due to augmented interlock. Specifically, compressing the joint with an initial protrusion height of 0.20 mm down to 0.08 mm results in an increase in interlock from 27.65 to 62.00 mu m, along with a 35.11% increase in tensile-shear strength and a 122.17% increase in cross-tension strength. The primary failure modes observed are neck fracture and pulling out. This article delves into the mechanical reshaping process of laser shock-clinched joints, aiming to improve their appearance and mechanical properties. The study includes a thorough analysis and comparison of clinched and reshaped joints. The findings indicate that reshaping results in a reduction in protrusion height, an increase in interlock, and an improvement in mechanical strength.image (c) 2024 WILEY-VCH GmbH