calculating stress intensity factor for small edge radial cracks on an orthotropic thick-walled cylinder subjected to internal pressure using the average stress

in this paper, the problem of calculating the stress intensity factor (sif) for an orthotropic thick-walled cylinder with a small radial crack subject to internal pressure is considered. the crack is assumed to be an edge crack on the external radius of the cylinder. the stress intensity factor is calculated by superposition of an uncracked cylinder with uniform stress distribution and a cylinder with a small radial crack. to calculate the stress distribution in the small radial crack, basic assumptions of the linear elastic theory have been used. due to the small length of the crack, an average stress method with a proper weight function is then used to evaluate the stress intensity factor of the assumed crack problem. simplifying the proposed formula for orthotropic cylinder to the isotropic one, the results are validated against data given in the literature search.