Analysis of Stress Intensity Factors for Surface Cracks Subjected to Arbitrarily Distributed Stresses

Summary

In recent years an effective method called the weight or influence function method has been developed to analyze the stress intensity factor, K, for surface cracks subjected to arbitrarily distributed surface stresses[1–5]. In this paper the authors will propose a new method which is based upon the superposition of the “unit distributed load” at each nodal point on the cracked surface.

A series of influence coefficients, K_ij, have been calculated for flat plates with a semielliptical or a quarter-elliptical surface crack of various aspect ratio, a/c, and depth to thickness ratio, a/t. It has been shown, based upon the data of K_ij, how easily the K-values for a surface crack can be evaluated for arbitrarily distributed stresses such as residual stress and unsteady thermal stress.