Effect of curing degree on forming of clinch-adhesive joint

ABSTRACT The clinch-adhesive joint has good mechanical properties and the curing degree of the adhesive during the clinching process shows significant impacts on the joint forming and its mechanical performance. During the clinching process, the interface of the cured adhesive layer restricts the flow of the metal thus shows a negative influence on the forming quality of the clinch-adhesive joint. This paper focuses on the interface layers change during the clinching process and the infulence of curing degree on the forming of clinch-adhesive joint by the finite element simulation model. Firstly, the constitutive model and interfacial failure criterion of Araldite 2015 epoxy adhesive considering curing degree were fitted through tensile tests for adhesive dumbbell specimens and bonding joints. Then, the forming process of the clinch-adhesive joints with fully cured adhesive were simulated. Finally, the effects of curing degree on the joint shape and interface failure were investigated. The results show that interface damage occurs at the location of the self-locking, and the curing degree mainly shows influences on the sizes of adhesive pocket and undercut, the damaged width of the interface layers, and the maximum damage of the interface layers.