Progressive Delamination Growth In Composite Laminates With Delamination Damage Under Fatigue Load

Composite laminates have been widely used in the aeronautics and astronautics industrybecause of their pretty mechanical properties. However, laminates are susceptible to low-velocityimpact which can lead to significant damage including matrix cracks, fiber fractures andinter-laminar delaminations etc. The internal damage can considerably reduce the safely servicelife of composite structures. To enhance the application level of composites, research on fatigueperformance of composite laminates containing prefab delamination damage should be carriedout.Based on the Mindlin first order shear deformation theory and ABAQUS software, a3D finiteelement model for simulating progressive delamination growth in composite laminates underfatigue load were performed. Based on damage theory, the strain-based failure criterion withcorresponding stiffness degradation technology, were adopted to the model during fatigue damage.The VCCT technology was used for modeling the region between two laminas. The initial andevolution of inter-laminar damage was decided by mixed mode energy released rate failurecriterion. And the interfacial damage near the interface crack tip and the development ofdelamination in the component were obtained. The total model was implemented by commercialfinite element software with its user subroutine. A good agreement was obtained betweennumerical analysis and experimental results. The effects of the parameters on the dynamicresponse and damage evolution of composites laminates were discussed, such as max stress level,initial delamination length and initial delamination location.