A new micromechanics based CDM model and its application to CMCʹs

A CDM theory is further developed in order to better model the non linear and dissipative behavior of Ceramic Matrix Composites. A new damage deactivation rule is developed, directly based on mechanics of microcrack behavior, considering both closure effects and the corresponding elastic energy storage. The complete model uses two sets of damage state variables, the scalar ones correspond to microcracks oriented by reinforcements and a second order tensor that evolves with the maximum principal strain directions. The model is applied to uniaxial and multiaxial monotonic and cyclic tests on a SiC/SiC composite. In addition, the new version of the damage deactivation rule allows a progressive effect and a better description of the residual strain.