A Micromechanical Damage Model for Uniaxially Reinforced Composites Weakened by Interfacial Arc Microcracks

A micromechanical anisotropic damage model is presented for uniaxially reinforced (brittle matrix) composites weakened by an ensemble of (fiber/matrix) interfacial microcracks. All microcracks are assumed to occur along the fiber/matrix interfaces, and are modeled as arc microcracks under “cleavage 1” deformation processes. Microcrack-induced strains and overall elastic-damage compliances are analytically derived based on micromechanical bimaterial (interfacial) arc-microcrack opening displacements and mesostructural probabilistic distributions. Both “stationary” and “evolutionary” damage models are given. In particular, microcrack kinetic equations are constructed based on micromechanical fracture criterion and mesostructural geometry in a representative volume element. Simple and efficient computational algorithms as well as some numerical uniaxial tension tests are also presented. Finally, it is noted that not a single arbitrary (fitted) “material constant” is employed in the present work.