Weight Functions and Stress Intensity Factors for Longitudinal Semi-Elliptical Cracks in Thick-Wall Cylinders

Abstract

Weight functions for the surface and the deepest point of an internal longitudinal semi-elliptical crack in a thick-wall cylinder (Ri /t = 1) were derived from a general weight function and two reference stress intensity factors. For several linear and nonlinear crack face stress, fields, the weight functions were validated against finite element data. Stress intensity factors were also calculated for the Lamé through the thickness stress distribution induced by internal pressure. The weight functions appear to be particularly suitable for fatigue and fracture analysis of surface semi-elliptical cracks in complex stress fields. All stress intensity factor expressions given in the paper are valid for cylinders with the inner-radius-to-wall-thickness ratio, Ri /t = 1.