Multiscale homogenization and damage failure analysis of composite materials with hierarchical distribution of pore defects

Composites with a multiscale distribution of pores are widely seen in nature and engineering. With the given total pore volume fraction, what is the influence of pore distribution pattern across scales on the effective mechanical properties of composites remains unexplored. Therefore, we develop a computational model to quantitatively study the cross-scale pore distribution effects on composites. A two-scale progressive damage method is proposed to capture the elastic and strength properties of composites with hierarchical microstructures, where the fibers embedded in matrix at different scales are modeled by imposing periodic boundary conditions on repeating unit cells (RUC). A recursive algorithm is proposed where the homogenized moduli and strength of lower scale microstructures are employed for the prediction of upper scales with fixed total pore volume fraction across two scales. The effectiveness of the model is verified by comparing the results with Chamis model. Parametric studies have been conducted for two kinds of composites, namely carbon-fiber and glass-fiber composites, showing that the optimized strength of composites may be achieved by the proper distribution of pore defects across scales. This work provides an efficient algorithm for studying pore defects redistribution effects across scales on effective moduli and strength of composites with hierarchical microstructures.