A conservative approach for mode Ⅰ-Ⅱ fatigue analysis under residual stresses: The RSIF proportionality conjecture

摘要

Residual stresses are a crucial aspect of fatigue life predictions of welded structures. However, their implementation in fatigue crack growth simulations can be tedious. In this paper, a novel approach is proposed that considers the effects of residual stresses in a worst-case scenario by applying the maximum tangential stress criterion and maximising the crack growth rate. Results demonstrate that computationally demanding analysis of residual stresses can be avoided by assuming the residual stress intensity factors are proportional to the stress intensity factors induced by the externally applied cyclic load. This approach is referred to as the residual stress intensity factors proportionality conjecture, which is particularly useful for inspection planning of complex structures subject to mixed-mode crack propagation situations, where the computational recovery of current residual stress states by consideration of their temporal evolvement is cumbersome.