Abstract:
Foreseeing how welded structures will behave requires careful consideration of the residual
stresses that the friction stir welding (FSW) process introduces. These residual stresses can cause
severe deformation and compromise the ability of friction stir welded structures to bear imposed
external loads. This work uses a Sequentially Coupled Thermo-mechanical finite element
simulation to quantitatively evaluate the influence of such residual stresses coming from the FSW
process. This modelling method examines the thermal and post-weld stress distributions during
the friction stir welding of dissimilar AA2024-T3 and AA5086-O alloys. The procedure entails an
initial thermal analysis followed by a mechanical analysis to determine the distribution of residual
stresses across the entire dissimilarly welded alloys. The study examined how alterations in FSW
operational parameters, such as rotational and translational speeds, influence both the thermal
conditions and residual stress distribution. The findings highlighted that both temperature and
residual stress exhibited higher values on the retreating side of the specimen compared to the
intended advancing side. As the tool rotational speed rose, the magnitude of longitudinal residual
stress dropped, however it showed an increase with greater tool translational speeds. Moreover,
the simulated outcomes demonstrate the substantial impact of welding fixtures on the profiles and
magnitudes of residual stresses.
