Residual Stress in Self-Piercing Riveting (SPR) Joints-A Review

Self-piercing riveting (SPR) is a high-speed method of joining sheet materials by creating a mechanical interlock between the sheets. Unlike conventional riveting, SPR does not require predrilling. Automobile industries adopted this joining technique because of its suitability in joining dissimilar materials and doing so at high-volume production. However, in SPR, the rivet plastically deforms and residual stress develops in the joint. The deformation behavior of the rivet and the residual stress distribution in SPR joints are poorly understood. This leads to difficulties in developing new product and optimizing the process. Development of new rivet and die geometries are also limited since the residual stress state in SPR joints are not fully described. Several key issues in modeling and measuring residual stress in SPR joints are discussed. How the plastically induced residual stress can be linked to the different phases of the riveting process is also described. This is an area of SPR with numerous prospects for research. It is expected that advancement will be achieved by a combination of techniques, including laboratory recreation, finite element modeling and manufacturing trials.