MODE-I STRESS INTENSITY FACTOR EQUATIONS FOR CRACKS AT NOTCHES AND CAVITIES

In this paper, the notch-crack problem is treated in two different way s: if the non-dimensional crack length l/rho (I = crack length; rho = notch root radius) is smaller than the transition crack length l(T)/rh o, it is treated as an edge crack lying within the local stress field around the notch tip; if l/rho is larger than l(T)/rho, the notch-crac k is considered as a simple flat crack problem subjected to remote loa ding the flat crack size being the sum of notch depth and the real cra ck length. Based on currently available numerical data, expressions fo r the transition crack length, l(T), and for the geometric factor F = K-I/(1.1215K(t) sigma root pi l) are developed for various notch probl ems for the crack length range l less than or equal to l(T). It is fou nd that the stress (sigma(yy)) normalized by the peak stress (sigma(pe ak)), sigma(yy)/sigma(peak), for the pre-cracked component is very sim ilar to the geometric factor for short cracks.