The effect of residual stress on mixed-mode crack propagation behavior
in friction stir welded 7075-T6 aluminum alloy panel under biaxial
In this work, the effect of residual stress on mixed-mode crack
propagation behavior in friction stir welded (FSW) 7075-T6 panel under
biaxial loading was investigated. The cruciform sample was designed and
manufactured by FSW. Residual stress profiles across the welded sample
were measured by the X-ray diffraction technique. Crack propagation
behaviors were simulated with five different biaxial loading ratios.
Stress intensity factors (KΙ and
KΙΙ) were evaluated by finite element method
(FEM) and used to study the effects of residual stress on crack
behaviors. It was observed that residual stress has a considerable
effect on the mixed-mode crack growth. In most of the cases, the crack
deflection is mainly affected by residual stress at the beginning of
crack propagation. The variation of crack propagation path is strongly
linked with the residual stress as well as the biaxial loading ratio. In
addition, KΙ and KΙΙ are
susceptible to residual stress under biaxial loading conditions.
Residual stresses contribute to a higher proportion of
KΙΙ compared to that of
KΙ. KΙ and
KΙΙ in the retreating side are more affected by
the residual stress.