Double-sided self-pierce riveting

This paper presents a new joining by forming process named as “double-sided self-pierce riveting” that makes use of tubular rivets with simple geometry placed in-between two sheets to be joined. The sheets are pushed against each other by flat parallel punches so that the rivets are forced through the sheets and their ends are flared (curled) to create mechanical interlocking’s which holds the sheets tightly together. The methodology draws from deformation mechanics and identification of major process parameters, to fabrication and destructive testing of joints. Experimental work in AA5754-H111 aluminum sheets and AISI 304 stainless steel tubular rivets was supported by finite element modelling. Results allow concluding that the new process incorporates the advantages of conventional self-pierce riveting and successfully overcomes its main disadvantages, namely the material protrusions above and below the sheet surfaces and the difficulties in joining sheets of dissimilar materials with large thicknesses. The new mechanical joints also have the advantage over those produced by clinching and self-pierce riveting of being invisible, because they are hidden inside the cross section of the overlapped sheets.