3D orthogonal woven carbon/carbon composites: micromechanical modeling and damage analysis

This study develops a progressive damage model for three-dimensional orthogonal woven car-bon/carbon composites using a micromechanical approach. An RVE (Representative Volume Element) model with periodic boundary conditions was constructed using the finite element method. The model includes fiber bundles, the matrix, and fiber bundle/matrix interfaces. Damage initiation in the fiber bundles and matrix is determined using the Hashin criterion and the maximum stress criterion, respectively, while the stiffness degradation method describes material behavior post-failure. The interface's mechanical behavior between the fiber bundles and the matrix is simulated using zero-thickness cohesive elements. Defects are introduced into this model using the Monte Carlo algorithm. Under various loading conditions, the predicted stress-strain curves and damage evolution closely align with experimental results, validating the model's ef-fectiveness. The results indicate that void defects significantly impact the material's strength and damage evolution, particularly under tensile loads. Analysis of stress-strain curves and damage states suggests that transverse damage in the matrix, interface, and fibers has a minor impact on the material's overall strength, whereas longitudinal fiber damage is the primary cause of material failure.words.