Modelling Material Flow in Friction Riveting of Polymeric Materials

This work gives a brief introduction to initial finite element models conceived to simulate the plastic deformation of the metallic rivet in polymer parts joined by Force-controlled Friction Riveting. Both the material flow and temperature evolution during the process were considered in the model. The final rivet deformation - i.e. the joint formation - was assessed by a set of measurements as described in literature for physical specimens. Validation of the computational models was performed with established parameters-to-joint formation correlations, based on data acquired via central composite design of experiments (CCD). The experimental maximum widths of the deformed rivet tip (W), were 7.0 mm and 9.3 mm, resulting from an initial diameter of 5 mm. This range of rivet plastic deformation corresponded to an energy-to-deformation efficient range (36- 77 J) of parameters used to produce the physical friction-riveted connections. A good correlation between the computational and the experimental results was achieved. This allows for predictive computational models to be used for joint design, with good estimations on joint tensile strength being drawn from the expected finite element models for joint formation.