Joining Strategies for Double-Sided Self-Pierce Riveting.

Double-sided self-pierce riveting (DSSPR) has been presenting itself as a proper alternative to self-pierce riveting (SPR) with many advantages for joining geometries of different thicknesses and cross-sections. To ensure its successful future industrial application, this paper presents a detailed comparison between different strategies to produce mechanical joints by means of the DSSPR process and discusses its performance and feasibility. Results show that the use of flat-bottom holes in both sheets provide interesting results, since they allow for a precise positioning of the tubular rivet in specific pre-defined locations, thus avoiding an incorrect joining procedure. This strategy tightens the tolerances of the process, while keeping a suitable level of destructive performance as demonstrated by the lap shear tests. Pre-riveting of the sheet has also been shown to produce suitable results in combination with or without a flat-bottom hole in the opposite sheet. This strategy comes at a cost of a slightly lower performance than that obtained with flat-bottom holes in both sheets, although the requirements of force and energy to complete the joining process are smaller. The conclusions of this research work are essential for selecting the joining strategy with DSSPR according to the requirements of the intended application.