Models for predicting crack growth rate and fatigue life

Abstract

Fatigue is a path-dependent process that involves crack initiation and propagation. The need to address these two processes simultaneously is apparent, so that material damage at the microscopic and macroscopic scale can be accounted for with consistency. From an engineering viewpoint, the interest is in how an initial crack begins to grow in fatigue and how it propagates during the stage of subcritical growth in a structural component. Historically, a high percentage of failures encountered for fracture critical parts has developed through propagation of the mixed mode crack. This crack may originate early in the life at areas of high stress concentration or they may develop from manufacturing defects present in the initial structure.