Influence of friction stir welding residual stresses on the compressive strength of aluminium alloy plates

•The longitudinal residual stress map in a friction stir welded plates' cross-section was determined using the contour method.•The main goal was to assess the influence of residual stresses on the collapse load of aluminium plates, subjected to compressive loads.•The influence of the magnitude of initial geometrical imperfections on the collapse load of aluminium plates, subjected to compressive loads, was also assessed.

The mechanical behaviour of welded structures can be significantly affected by the effects of the employed joining process. The main goal of this work is to assess the influence of the longitudinal residual stresses on the overall compressive performance of aluminium friction stir welded plates. Longitudinal residual stress distribution was measured by means of the contour method and introduced as initial condition into a finite element model of the compressed assembly. Also, the sensitivity of the plates to the magnitude of the initial geometrical imperfections was analysed. It can be inferred that both factors influence the plate's mechanical behaviour.