FEM Analysis of the SIF in Rotating Shafts Containing Breathing Elliptical Cracks

Abstract

Failures due to the propagation of fatigue cracks in shafts are one of the most common problems in rotating machines as they can cause irreversible damage and put lives at risk. The main parameter for the study of crack propagation is the Stress Intensity Factor. When a cracked shaft rotates, the transverse crack contained in it presents the opening and closing mechanism (“breathing mechanism”). Although most of the studies on cracked shafts consider straight cracks, the real fatigue cracks have a semi-elliptical front. In this work, the numerical analysis of the Stress Intensity Factor along the entire front of a semi-elliptical crack during the rotation of the shaft has been developed taking into account the breathing mechanism.