New progress in micromechanics-based CDM models and their application to CMCs

A previously developed continuum-damage theory for modeling ceramic-matrix composites is modified relative to the deactivation rule. The new deactivation is directly based on mechanics of microcrack behaviour, considering both closure effects and the corresponding elastic energy storage. The model uses two sets of damage state variables, scalar ones corresponding to microcracks oriented by reinforcements and a second rank 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.