Progressive fatigue failure analysis of open-hole composite laminates: High-fidelity simulations and an experimental study

A high-fidelity progressive fatigue damage model was developed to predict static strength, fatigue life, and post-fatigue residual strength of open-hole composite laminates. The framework integrates continuum damage mechanics with inter- and intralaminar cohesive zone modeling to capture intralaminar matrix cracking, delamination, and their interactions. The enhanced LaRC05 failure criteria were implemented to simulate fiber breakage, pull-out, kinking, crushing, splitting, and matrix cracking. To enable rapid model preparation, an Abaqus pre-processing plugin was created. The developed fatigue damage model can predict the behavior of the multidirectional laminate under arbitrary stress levels, stress ratios, and loading sequences using a limited experimental dataset of unidirectional laminates tested in the longitudinal, transverse, and shear directions. A block-loading approach combined with an adaptive cyclic-jump method was employed to reduce the computational costs of high-cycle fatigue simulations while preserving physical fidelity. The framework also enables element-wise tracking of residual stiffness and strength, which is valuable during the design stage for identifying fatigue-prone regions. The model was validated via experimental testing of IM7/977–3 [0/45/90/-45] 2s open-hole specimens under tensile and compressive static loadings, tension–tension (R = 0.1) and tension–compression (R = -1) fatigue loadings, as well as tensile and compressive residual static strengths of fatigued laminates. The predicted stress–strain responses, S–N curves, and residual tensile and compressive strengths agreed closely with the experimental results, demonstrating the model’s accuracy for virtual testing and life prediction of composite structures containing stress concentrators.