Characterization methods of delamination in a plain woven CFRP composite

A plain woven carbon fiber reinforced polymer is characterized concerning its delamination behavior. The results of the mode 1 fracture test show the significant run-arrest behavior of the investigated composite. To evaluate the compatibility of the data reduction method based on the modified beam theory, which has been introduced in the ASTM D5528, another method based on the linear elastic fracture mechanic is also performed to calculate the initial fracture toughness. The results from both data reduction methods correlate with each other very well. Meanwhile, the mode 2 fracture tests with non-precracked and precracked specimens are performed. The compliance calibration results indicate the negligible discrepancy between the two groups, which demonstrates the feasibility of ASTM D7905 for acquiring the initial fracture toughness. Based on the fracture toughness parameters calibrated from the aforementioned tests, the finite element models with a cohesive zone model are built and successfully simulate the delamination behavior in both the mode 1 and mode 2 fracture tests. A side finding is that the traction strength for both fracture modes is sensitive to the element size, which is investigated in detail in this study.