Self-pierce riveting of tubes to sheets

This paper presents a new joining by forming process capable of attaching a sheet to the end of a tube without the need of accessories and extra materials. The process is named as ‘self-pierce riveting of tubes to sheets’ and is an extension to sheet-tube connections of the working principle of double-sided self-pierce riveting utilized for connecting two overlapped sheets. The process requires tubes with chamfered ends to be pushed against the sheets and its ends to flare (curl) in order to create an interlocking that holds the sheets and tubes tightly together. The resulting joints are invisible because the interlockings are hidden inside the sheets. The presentation draws from deformation mechanics and identification of the major parameters to characterization of the interlocking and evaluation of the pull-out destructive strength that the new joints are capable to withstand without failure. Aluminium sheets and carbon steel tubes are utilized to demonstrate the effectiveness of the new joining by forming process and to demonstrate its ability to connect sheets and tubes made from dissimilar materials at room temperature. Finite element modelling using an in-house computer program gives support to the presentation.