Comparative study on two compressing methods of clinched joints with dissimilar aluminum alloy sheets

Mechanical clinching technology has been widely used to join aluminum alloy sheets in the automotive body. One of the disadvantages of the clinched joint is the high protrusion above the sheet, which may limit the application of the mechanical clinching technology in the visible areas. In order to reduce the height of the protrusion, two compressing methods were investigated with dissimilar aluminum alloy sheets in this paper. Both the two compressing methods can increase the strength of the joint. The height of the protrusion was reduced significantly in the compressing process. The absorption capability of the energy in the failure process was also increased by the two compressing methods. The compressing method with a flat die and a bumped die has a better performance than the compressed joint produced by a pair of flat dies. Neck fracture mode is the main joint failure mode in the strength test. The strength of the joint can be increased with the compressing methods by increasing the neck thickness in the compressing processes.