Mechanically consistent continuum damage model for anisotropic composites including damage deactivation

Due to crack bridging effects, ceramic matrix composites (CMCs) have outstanding properties that combine a quasi-ductile material behaviour with the high-temperature properties of ceramics. Combined with their high specific strength, this makes them perfectly suitable for high temperature safety relevant components. In view of the design process of CMC components elaborated continuum damage models are required that most importantly consider their anisotropy and damage deactivation effects in a mechanically and mathematically consistent manner. With respect to their damage effect, most of the existing anisotropic models fail with regard to the damage growth criterion leading to the unphysical effect of an increasing stiffness due to damage. Motivated by the modelling process of initially anisotropic composite materials like CMCs, this paper presents the systematic formulation and validation of a mechanically consistent damage effect model together with crack closure effects.