Numerical and experimental investigations of the two-step clinching process with a bumped die

Abstract

In order to increase the shearing strength and reduce the protrusion height of the clinched joint, a two-step clinching process was designed and investigated in the study. A clinching machine produced by Express Company and extensible dies were used to produce the clinched joint, while a flat die and a bumped die were used to produce the two-step clinched joint. A 2D model in the software DEFORM-2D was applied to analyze the material flow and effective stress distribution of the two-step clinched joint. To validate the numerical model, experimental tests were carried out to get the main geometrical parameters of the two-step clinched joint. The two-step clinching method could increase the neck thickness with the decrease of the protrusion height. Shearing tests were carried out to obtain the shearing strengths of the two-step clinched joints. The results showed that the shearing strength and energy absorption of the joint could be increased by the two-step clinching process because of the increased neck thickness. The two-step clinching method was proved to be effective for increasing the shearing strength and energy absorption of the clinched joint.

Keywords

• two-step clinching
• deform
• material flow
• strength
• energy absorption