Fatigue growth simulation of part-through flaws in thick-walled pipes under rotary bending

The fatigue growth of a circumferential external surface flaw in a thick-walled round pipe subjected to rotary bending is simulated numerically. A three-dimensional finite element analysis is carried out to obtain the stress–strain field of the cracked structural component for any position of the flaw. The crack front is assumed to have an elliptical-arc shape during the whole propagation, as has been deduced from several experimental investigations. The results for rotary bending are compared to those for cyclic bending.