Simulation on damage in quasi-isotropic fiber-reinforced composite laminates under open-hole tension

A new 3D finite element model was established, which had been used to simulate the open-hole tensile damage of quasi-isotropic fiber-reinforced composite laminates with stacking sequences of [45/0/-45/90]_s and [45/-45/90/0]_s. Each ply was modeled by 3D solid elements (C3D8R in ABAQUS notation). Because the matrix constituent is much weaker than the fiber, longitudinal splitting or matrix cracking may take place at a very low tensile load due to the local shear force near the hole edge. The longitudinal splitting can blunt the hole and alleviate the stress concentration. And the load-carrying capacity of the material will be enhanced. In order to accurately simulate the damage of the laminates, two surface-based cohesive contacts had been inserted tangential to the hole along the fiber direction in each ply (except for the 90° ply) to simulate the intra-ply longitudinal splitting. Meanwhile, surfaced-based cohesive contacts had also been used to simulate the inter-ply delamination characteristic. In order to improve the computation efficiency and guarantee the calculation accuracy, fine mesh had been used within the region around the hole and relative coarse mesh in other regions. Within the cohesive zone, a certain number of elements was ensured, so that we can both accurately capture the stress distribution and alleviate the mesh dependency. When compared with experimental data in published literature, a good agreement is achieved.