Compressive failure analysis of unidirectional carbon/epoxy composite based on micro-mechanical models

A 2D micro-mechanical model was proposed to study the compressive failure of UniDirectional (UD) carbon/epoxy composite. Considering the initial imperfection and strength distribution of the fiber, the plasticity and ductile damage of the matrix, the failure of T300/914 UD composite under longitudinal compression and in-plane combined loads was simulated by this model. Simulation results show that the longitudinal compressive failure of the UD composite is caused by the plastic yielding of the matrix in kink band, and the fiber initial imperfection is the main reason for it. Under in-plane combined loads, the stress state of the matrix in kink band is changed, which affects the longitudinal compressive failure modes and strength of UD composite. The failure envelope of σ1-τ12 and σ1-σ2 are obtained by the micro-mechanical model. Meanwhile, the compressive failure mechanism of the UD composite is analyzed. Numerical results agree well with the experimental data, which verifies the validity of the micro-mechanical model.