Probabilistic micromechanical damage model for mixed mode I/II fracture investigation of composite materials

The non-linear behavior of cracked body composite materials can originate from toughening mechanisms in the crack-tip damage zone. Given the damage zone complexity, the residual strength and overall compliance of micro-crack-weakened solid are used for characterization by a micromechanical damage approach. In the present research, a mixed mode I/II criterion called “damage zone micro-mechanical criterion” is presented for composite materials. In this context, a semi-empirical image processing method and relative probabilistic functions are employed to characterize the moment of crack propagation based on the dispersion of orientated elliptical micro-cracks. In addition, it is assumed that the micro-crack growth occurs in isotropic matrix where fibers play as reinforcement of the matrix by utilizing stress reduction coefficients. In this research, a remarkable precision is obtained considering micromechanical criterion in comparison with experimental data.