On the effect of pilot holes on the mechanical behaviour of flow-drill screw joints. Experimental tests and mesoscale numerical simulations

Abstract

This research work investigated in detail the mechanical performance of a flow-drill screw connection of two aluminium plates with and without pilot holes. An extensive experimental campaign involving material and joint tests under different loading modes is presented. These tests are supported by numerical models. Detailed solid-element models provided meaningful information about the local deformation mechanisms of the tested configurations, and allowed to identify the reason behind the early screw failure observed in some of the experimental joint tests. Moreover, several geometrical features of the connection were found to be relevant for the mesoscopic model, so their influence was assessed. The combination of experiments and simulations provided robust and meaningful understanding of the connections.