A novel investigation of microcrack-induced degradation in fiber-reinforced composites using peridynamic unit cell homogenization

This study presents an extensive parametric analysis of how microcrack configuration influences the effective properties of composite structures at the macroscale, employing the peridynamic unit cell (PDUC) homogenization method. Built on the nonlocal formulation of peridynamics, PDUC represents damage through bond breakage and enforces periodicity in a bond-consistent manner within the unit cell, thereby enabling homogenization in the presence of structural discontinuities without remeshing. The mathematical formulation and implementation of the PDUC framework are described, followed by rigorous verification against benchmark problems from the literature for both intact and damaged unit cells. The implementation consistently returns accurate effective moduli under the six standard macroscopic unit strain loadings and is readily applicable to orthotropic constituents and complex micro-architectures. Utilizing this verified implementation, parametric studies are systematically conducted on a carbon fiber-epoxy representative unit cell to assess the effects of microcrack size, orientation, spatial randomness, and phase location on the homogenized response. The resulting framework and findings supply actionable insight into the sensitivity of effective properties to microcrack descriptors and provide a practical route for incorporating evolving micro-damage into constitutive models of fiberreinforced polymers and related composite systems.