Notched shells with surface cracks under complex loading.

In the present paper, a double-curvature thin-walled shell with a circular-arc notch is considered. For different notch configurations, the stress-intensity factor (SIF) along the front of an elliptical-arc surface crack at the notch root is computed through a three-dimensional finite element analysis, for seven elementary stress distributions perpendicular to the crack faces. Then, by employing such results, an approximate expression of SIF in the case of a generic complex loading is determined by means of the power series expansion of the actual stress field and the superposition principle. Finally, as an example of how to apply the above numerical procedure, the effect of the stress concentration on the SIF values is examined for both cylindrical and spherical notched shells under an internal pressure.