Daralan kesitli kompozit tabakalarda hasar ıncelenmesi

In this study, damage in tapered composite laminates under tensile loading is investigated. The cohesive zone method is used to simulate the delamination failure. For simulation of intralaminar damages, a 3-D continuum damage mechanics-based model with Hashin criteria is employed. Finite element analyses are implemented in Abaqus/Explicit. In addition to loads corresponding to delamination onset, both delamination locations and propagation characteristics are also utilized for making comparisons between computational results and experimental observations. Dynamic characteristic of delamination is employed to validate numerical analyses, further. The delamination predictions are compared to images taken by a high-speed camera. Results show that the ply drop-off type influences laminates strength and governs the delamination growth to be either stable or unstable. A good correlation between experimental and FE results is observed in terms of delamination onset location, propagation patterns, and stability of delamination growth. For some specimen types, a modified cohesive strength pair is required to enhance these correlations. To further investigate the local delamination behavior around the resin pocket, combinations of unidirectional plies with 0° and 45° orientations for a laminate with a single, double, and three drop-offs are considered as well. In addition to delamination patterns, the load transfer mechanism in the drop-off region, is also studied. A different delamination behavior for each case shows the significance of the effect of orientation of each sublaminate on the load transfer mechanism. Also, results show that the progression of delaminations within various interfaces to be similar for both 2-D and 3-D models in laminates with 0° plies. However, there are some differences in laminates, including 0°. Also, the 3-D model clarifies the significance of ply orientation in delamination propagation patterns, which is not detectable in the 2-D model.