关键词: 自冲铆, 上限法, 冲压载荷, 参数反演

Abstract: Based on the virtual work principle of material plastic deformation and the upper bound theorem, the inverse analysis of maximum riveting force in the SPR processes was carried out. The inverse calculation model of maximum riveting force was established by taking the geometric characteristic parameters of the joints, such as rivet flaring, rivet geometry parameters, thickness of the connected material, mechanics properties of rivet and connected material, contact conditions between punch and rivet as the model control parameters. At the same time, the verification tests were carried out on the maximum riveting force for a variety of aluminum alloy SPR processes. The results show that average error between the model calculation value and test value is as 7.82%, which verifies the validity of the inversion model for the maximum riveting force. The maximum riveting force is proportional to the strength and length of the rivet and inversely proportional to the depth of the rivet cavity. To obtain self-piercing riveted joints with higher static performance, the maximum riveting force should be appropriately increased. In addition, under the action of near maximum riveting force, the connection materials with lower hardness and rivets with lower hardness are easy to obtain joints with large rivet flaring.

Key words: self-piercing riveting(SPR), upper bound limit method, riveting force, parameter inversion