Mode I interlaminar fracture toughness of woven glass/epoxy composites with mat layers at delamination interface

Abstract In this study, double cantilever beam (DCB) specimen was employed to take into account the effects of mat layer at delamination interface on mode I fracture toughness of woven glass/epoxy laminated composites. DCB specimens were made using hand lay-up method assisted by the vacuum bagging technique. The experiments revealed that the mat-interlayer changed crack propagation mechanism, reducing the initiation and propagation fracture toughness during mode I interlaminar tests, by 80 and 69%, respectively. Also, the results show that fiber bridging is not the main mechanism for increasing fracture toughness in DCB samples without mat interlayer. Moreover, for numerical simulation of delamination propagation in DCB samples, the cohesive traction was measured in tests using J-integral approach. Comparing load-displacement response curves of numerical and experimental results, proved that the proposed cohesive zone model capable of precisely predicting the experimental load-displacement curve.