Matrix Cracking and Induced Delamination in Symmetrically Laminated Composites Subjected to Static Loading by using Multi Scale Damage Mechanics

Matrix Cracking and induced delamination in symmetric cross-ply, [0m/90n]s, and angle-ply, [θ/-θ]s, laminated composites under axial and shear loading are studied by multi-scale micro-meso approach. The stress transfer model is implemented to predict the stress and displacement distribution incorporated with the ply-refinement technique in laminates. By considering crack closure condition, a series of useful inter-relationships between thermo-elastic constants for damaged and corresponding undamaged laminates are derived. By using both of stress and displacement fields and these inter-relationships the properties of damaged laminated structure are achieved. These obtained properties are used to calculate the energy release rate in load control condition for the initiation and growth of matrix cracking and induced delamination in cross-ply symmetric laminates with [0m/90n]s layup. The obtained results of mechanical properties degradation show a good agreement with the results of experiments, variational approach and finite element methods (FEM) existed in literature. By comparing the results of the energy release rate of single-layer method with variational approach and finite element methods, it was observed that the results of proposed single-layer have a considerable error due to differences in slop of stiffness versus crack density.Finally, the accuracy of single-layer micromechanical approach in predicting the mechanical properties and inaccuracies in predicting of energy release rate was confirmed