Extended finite element modeling of fatigue crack growth microstructural mechanisms in alloys with secondary/reinforcing phases: model development and validation

Light structural metals have been extensively applied throughout the transportation sector in recent years with greater impetus to reduce vehicle weight and enhance energy efficiency. However, their use is restricted by the engineering challenge of fatigue crack growth and the need to understand, simulate, and predict crack propagation mechanisms with respect to materials' microstructure. To address this need, a comprehensive computational methodology has been developed using the extended finite element method to predict fatigue crack interaction mechanisms with characteristic microstructural features. Mathematical formulations and algorithmic development are rigorously addressed, with specific emphasis on the incorporation of relevant physical phenomena of plasticity and particle debonding/fracture. This approach is validated by comparison with analytical models and experiments on cast aluminum-silicon alloys using digital image correlation. The proposed methodology constitutes a framework for the successful development, application, and advancement of computational design of materials. Ultimately, this contributes to material/process selection and design for structural integrity by enabling rapid assessment of fatigue crack growth resistance without prior testing, thereby reducing of the extent of costly experimental investigations.