Stress intensity factors for radial cracks in annular and solid discs under constant angular velocity

Abstract

The finite element method has been used to predict the stress intensity factors for single- and double-edge cracks in six annular and solid rotating discs under constant angular velocity. Linear elastic fracture mechanics finite element analyses have been performed and the results are presented in the form of crack configuration factors for a wide range of component and crack geometry parameters. These parameters are chosen to be representative of typical practical situations and have been determined from evidence presented in the open literature. The extensive range of crack configuration factors obtained from the analyses are then used to obtain equivalent prediction equations using a statistical multiple non-linear regression model. The accuracy of this model is measured using a multiple coefficient of determination, R2, where 0 ≤ R2 ≤ 1. This coefficient is found to be greater than or equal to 0.98 for all cases considered in this study, demonstrating the quality of the model fit to the data. Predictive equations for stress intensity factors enable designers to predict the fatigue life of these components easily. It is also suggested that one of the component configurations (i.e. the cracked slit rotating disc) can be selected as a suitable experimental sample to measure the real fracture toughness of rotating components, using the relevant predictive equation presented in this study. Finally a fracture criterion is also suggested graphically to determine the limit load value of angular velocity for similar rotating disc components.