Analysis of stress intensity factors for surface cracks subject to arbitrarily distributed surface stresses.

A weight function method has been developed to analyze the stress intensity factors for surface cracks which are subject to arbitrarily distributed surface stresses. The method is based upon the superpositon of the unit distributed load at each nodal point on the cracked surface. It can be easily incorporated with the ordinary three dimensional finite element code which utilyzes the 20-noded isoparametric elements with quadratic shape functions. Some examples in the paper show that the method guarantees the reasonable accuracy and that it is effective especially for the analysis of unsteady thermal stress problems.