Experimental investigation of the mechanical reshaping process for joining aluminum alloy sheets with different thicknesses

In recent years, mechanical clinching technology has attracted more and more attentions. However, the high protrusion on the clinched joint may limit the application of the mechanical clinching technology. In the present study, a reshaping method for the clinched joint with different sheet thicknesses to reduce the protrusion height was investigated. The reshaping process is a complementary process for the clinched joint. A flat die and a bumped die were used to reshape the clinched joint. Al5052 aluminum alloy sheets with thicknesses of 2.0 mm and 2.5 mm were used in the present study. The interlock between the sheets was not damaged, and the sheets were still joined together after the reshaping process. The geometrical parameters, failure mode, tensile strength, shearing strength and energy absorption of the joints were investigated by experimental method. The neck thickness of the joint can be enlarged by the material flow in the reshaping process. Neck fracture mode is the main failure mode of the joint in this study. The reshaped joint produced by the Al5052 sheet with a thickness of 2.5 mm (upper sheet) and the Al5052 sheet with a thickness of 2.0 mm (lower sheet) has the highest average strength, and the clinched joint produced by the Al5052 sheet with a thickness of 2.0 mm (upper sheet) and the Al5052 sheet with a thickness of 2.5 mm (lower sheet) has the lowest average strength. The reshaping process not only can reduce the protrusion height, but also can contribute to increase the strength and energy absorption of the joint.