Based on the FEM software of Defrom-2D, the model and forming processing of sheet clinched joint were respectively built and analyzed. The results show that the cause for forming of S-neck is the different forming velocities of sheet during the process of sheet clinched joint. The forming process includes four stages, that is stage of prepared punching, stage of pre-forming, stage of die groove filling and stage of holding pressure. During forming process, the forming force required for clinched joint periodically and continuously increases. While the blank holder force is basically unchanged at the stage of initial forming, to some extent declines at the stage of die groove filling, and sharply rises at the stage of holding pressure. The experimental results show that the shear strength and tensile strength are 112 and 550 MPa respectively, which meet the requirement of joint strength.
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