Research on the forming quality of clinched joint for dissimilar sheet metal

The clinched process of heterogeneous materials is increasingly used in automobile, aerospace, and household appliances manufacturing. To investigate the forming quality of clinched joint for dissimilar sheet metal, the clinching experiments are carried out, and the cross-section morphology of clinched joints is observed. The finite element model for forming steel-aluminum clinched joint is established. The influence of process parameters (forming process parameters, geometry parameters, and concave die structural parameters) on the forming quality of steel-aluminum clinched joint is analyzed. The evaluation of the joint after forming includes the critical dimension, deformation, and neck-lock ratio. Then, the strength of the joint is measured by the tensile shear test. The changing law of strength and the neck-lock ratio is analyzed. The design strategy of different process parameters is proposed. The results show that the forming process of the joint is well predicted by numerical simulation, and the joint quality is good. The neck lock ratio of the joint with the highest tensile and shear strength is close to 1 when the forming force is 40 kN. The tensile strength and shear strength of the joint are increased by 125% and 62.35%. The design strategy is verified by experiments. The shear strength of the joint is increased by 16.49%.