Accuracy of Determining Stress Intensity Factors in Some Numerical Programs

At present, there are many programs for numerical analysis of cracks, in particular for determining stress intensity factors. Analyses of a single-edge cracked beam and flat plate with a semielliptical surface crack are presented in this study to examine the accuracy and applicability of the Franc2d and Franc3d programs. Further numerical computations of the MARC program and analytical solutions of stress intensity factors were included to compare the results with each other. For this purpose MARC was equipped with special user procedures. The influence of mesh fineness on the results was also investigated in all programs. The distributions of the stress intensity factors show good agreement in quality. The maximum deviations from the analytical solutions are 9.7 %. With greater numbers of elements programs Franc2d and Franc3d showed some instability, which currently reduces the usefulness and reliability of these promising tools for engineering applications.