A new modeling of plasticity coupled with the damage and identification for carbon fibre composite laminates

The research described herein was aimed at gaining a better understanding of the behavior up to the fracture of laminate composite structures. An elastoplastic damage model was developed to describe the behavior of these structures in the greatest detail possible. The damage is modeled on each elementary constituent. Then a complete model at meso (intermediate) scale is obtained by applying a homogenization method. This model takes into account the transverse tensile and shear damage of matrix and fibre–matrix interface, as well as the nonlinear behavior of the fibre under axial compression. Plasticity develops only in the matrix and its flow is blocked in the direction of the fibres. It is modeled by an anisotropic yield criterion (of the HILL type) which takes not only the transverse and shear stress into account but which also includes isotropic and nonlinear kinematic hardening. The model developed was included in the nonlinear finite element “Castem 2000” to allow comparisons between numerical and experimental results. There is a good agreement between the simulated and experimental data. However, the model could advantageously be extended to take the phenomena such as viscoplasticity into account.