CALCULATION OF STRESS INTENSITY FACTORS FOR SEMIELLIPTIC CRACKS IN A THICK-WALL CYLINDER

Weight functions for the surface and the deepest point of an internal semielliptical crack in a thick-wall cylinder were derived from a gene ral weight function and two reference stress intensity factors. For se veral linear and nonlinear crack face stress fields, the weight functi ons were validated against finite element data. Stress intensity facto rs were also calculated for the Lame through the thickness stress dist ribution induced by internal pressure. The weight functions appear to be particularly suitable for fatigue and fracture analysis of surface semielliptical cracks in complex stress fields. All stress intensity f actor expressions given in the paper are valid for cylinders with an i nner radius to wall thickness ratio, R(i)/t = 4.