Effect of internal pressure on plastic loads of 90° elbows with circumferential part-through surface cracks under in-plane bending

This paper quantifies the effect of internal pressure on plastic loads for elbows with circumferential through-wall and constant-depth part-through surface cracks under in-plane bending. Results are based on FE limit analyses using elastic-perfectly plastic materials and the non-linear geometry option. It is found that, for larger values of r/t, the pressure effect on plastic loads is more pronounced and plastic loads for combined loading cases could be much higher than those for pure bending cases. Full FE data of plastic loads are tabulated, and effects of crack geometries on interaction curves are discussed.