Comparative investigation of auxiliary processes for increasing the strength of clinched joints

Mechanical clinching has been widely used in the field of automotive industry in recent years. However, the clinched joint has a lower static strength than spot welding. In order to increase the static strength, a comparative investigation of two auxiliary processes for increasing the strength of clinched joints was carried out. One auxiliary process needs a rivet, while another auxiliary process needs a bumped die. Tension-shearing strength tests and cross-tensile strength tests were conducted to assess the static strengths of the joints after different auxiliary processes. Failure mode of all the joints was neck fracture in the tension-shearing strength tests and cross-tensile strength tests. Geometrical parameters of the joint profile were also investigated by comparing the two auxiliary processes. The values of energy absorption of different joints were obtained by measuring the areas between the force–displacement curve and x-coordinate. The two auxiliary processes were proved to be effective. The auxiliary process with a rivet has a better performance than the auxiliary process with a bumped die.