Fatigue crack growth prediction in polym

Fatigue damage remains a major challenge in the design of composite structures, as cracks may initiate under low stress levels and evolve through multiple interacting failure mechanisms. To reduce reliance on extensive physical testing, finite element methods based on progressive damage analysis are increasingly used to predict fatigue-driven crack growth within structural substantiation workflows. However, most existing approaches require prior knowledge of the crack path, limiting their ability to represent complex, solution-dependent fracture trajectories. The eXtended Finite Element Method (XFEM) offers a promising alternative, as cracks can be modeled independently of the mesh, yet commercial implementations remain limited for fatigue loading. This work introduces a fatigue-capable XFEM framework that combines the cohesive segments approach with a stress–life-based degradation law using only Abaqus built-in user subroutines and native elements. The framework is verified against a classical Cohesive Zone Model (CZM) and applied to a two-dimensional single element model as well as Double Cantilever Beam (DCB) specimen under Mode I static and fatigue using the IM7/8552 carbon/epoxy material system. The results demonstrate excellent convergence between the proposed method and CZM approach for the single element model, providing a practical alternative for simulating progressive damage in composite structures.