Scaling effect in notched composites: The Discrete Ply Model approach

Numerical and experimental investigations were carried out on the size effect in notched carbon/epoxy laminates. This paper presents a computational study of scaled open-hole tensile tests using the Discrete Ply Modeling (DPM) method, which has already proven efficient on both in-plane and out-of-plane loading cases, such as pull through, low velocity impact and compression after impact. The specificities of this finite element model are its discrete nature, the small number of parameters required and its robustness. Three different stacking sequences of thin plies coupled with three sizes of coupons having the same length to width ratio were tested. The results show that the model reflects the reduction in strength when the size of the specimen increases. The influence of different parameters such as mesh size, presence of discrete matrix cracks and fiber fracture toughness that should be used for clustered plies, are discussed. Comparisons with experiments demonstrate that tensile strengths, and failure scenarios and patterns are predicted with acceptable accuracy.