Weight functions and stress intensity factors for embedded cracks subjected to arbitrary Mode I stress fields

Fatigue cracks in welded, shot peened and case hardened machine components are subjected to various stress fields induced by the load and the residual stress. Both stress field types are highly non-linear and appropriate handbook stress intensity solutions are unavailable for such configurations. The method presented below is based on the generalized weight function technique enabling the stress intensity factors to be calculated for planar cracks subjected to any Mode I stress field. Both the general weight functions and the calculated stress intensity factors are validated against numerical and analytical data. The numerical procedure for calculating stress intensity factors for arbitrary non-linear stress distributions is briefly discussed as well The method is particularly suitable for modeling fatigue crack growth of single buried elliptical and multiple cracks.