Initial and final failure strength analysis of composites based on a micromechanical method

In this paper, a micromechanical model for investigating initial and final failure surface of fiber-reinforced composites laminate is established. The Generalized Method of Cells, which effectively predicts the thermal stresses influence on stress-strain behaviors of fiber-reinforced composites, is combined with Von-Mises yield criterion to describe nonlinear stress-strain behaviors of composites laminate. The Tsai-Hill criterion is incorporated into the model for predicting failure strength of lamina and typical laminate in uniaxial tension and biaxial loading, respectively. The numerical simulations based on a micromechanical method are performed to study the effects of thermal residual stresses on initial and final failure strength. Results revealed that thermal residual stresses influence on failure strength of the UD lamina is closely dependent on fiber off-axis angles. The contribution of thermal residual stresses in the final failure surface of [0°/±30°/90°]2 laminate and [90°/±45°/0°]2 laminate can be ignored. The results in longitudinal for lamina and biaxial tensile loadings for [90°/±45°/0°]2 laminate show good agreement with the experimental data.