Progressive damage analysis of open-hole CFRP laminates under combined tension-shear loading

Progressive damage and strength analysis in an open-hole tension test is crucial in designing carbon fiber-reinforced polymer (CFRP) composites. In practical applications, loading is of multi-axial in nature, making the damage process more complex in CFRP structures. This work proposes a generic continuum damage mechanics-based 3D progressive damage model incorporating the LaRC05 failure criteria. The proposed formulation, coupled with cohesive surface modeling, is benchmarked against existing open-hole CFRP laminate test results under a combined tension-shear loading scenario. Later, the effect of laminate layup on the strength, damage initiation, and evolution is studied by considering two types of QI, a 0°, and 45°dominated layups. As observed in the experimental studies, the proposed model can predict distinct dominant failure mechanisms and also the critical loading angle at which the failure mechanism switches from one to another. Further, in case of a combined loading, the damage modes, such as fiber kinking and the extent of fiber splitting, dominate the failure, which is well-captured by the proposed model. Further, it is able to predict the failure strengths accurately for all combined loading scenarios and laminate types with a maximum error of 14.7%, which confirms the robustness and accuracy of the proposed model.