Progressive Failure Analysis of Composite Laminates Under High-Cycle Fatigue
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Fatigue is often a critical load case in fiber reinforced polymer composites. To reduce the time and costs associated with experimental testing procedures, accurate simulation methods must be developed from coupon level up to the larger component level with more complex geometries and designs. Several numerical models have been proposed in the past years to simulate fatigue crack propagation in fracture characterization specimens. However, progressive fatigue failure modeling of laminates, where cracks can initiate and propagate and where interaction of several failure processes such as fiber breakage, transverse matrix cracking and delamination takes place, is still a challenging task. Moreover, in multidirectional laminates, thermal residual stresses are present which can alter the local stress ratio and stress fields. In this work, a robust and efficient mesoscale simulation framework is presented that considers initiation and propagation of matrix cracks and delamination under high-cycle fatigue loading. A recent mixed-mode fatigue cohesive zone model has been improved and combined with XFEM to simulate mesh-independent intra-laminar cracks. Furthermore, the framework utilizes a cycle jumping scheme to capture local stress ratio variations as a result of the curing process. It is demonstrated with numerical examples that the model is capable of accurately simulating the interaction between transverse matrix cracks and delamination. The numerical results are compared against experiments of quasi-isotropic open-hole laminates and show good correlation in terms of fatigue life and damage evolution.