Calculation of Stress Intensity Factors Based on Through-Thickness Stress Data From ANSYS Analysis

Abstract

In this paper, an approach is developed to determine polynomial stress distributions across a shell based on through-thickness stress data from an ANSYS [1] analysis. The polynomial stress distributions can be used to calculate stress intensity factors based on the requirements in different design codes. In ASME Code Section XI, Appendix A [2], polynomial stress distributions or linearized stresses over the flaw depth may be used to calculate the stress intensity factors for a flaw. Impacts on stress intensity factors by using polynomial stress distributions, and linearized stresses over the flaw depth or over the thickness are investigated based on the procedure in ASME Code Section XI. The results from using linearized stresses over the flaw depth are close to the results using polynomial stress distributions. Using linearized stresses over the thickness is un-conservative for a concave upward stress distribution with increasing slope across the thickness and conservative for a concave downward stress distribution with decreasing slope across the thickness.