Elastoplastic Micromechanical Analysis of Fiber‑Reinforced Composites with Defects

The objective of the present work is the computational micromechanical analysis of unidirectional fiber-reinforced composites, considering defects. The micromechanical model uses refined beam theories based on the Carrera unified formulation (CUF) and involves using the component-wise (CW) approach, resulting in a high-fidelity model. Defects are introduced in the representative volume element (RVE) in the form of matrix voids by modifying the material properties of a certain quantity of the Gauss points associated with the matrix. The quantity of Gauss points thus modified is based on the required void volume fraction, and the resulting set is prescribed a material property with negligible stiffness to model voids. Two types of void distribution are considered in the current work—randomly distributed voids within the matrix and voids clustered in a region of the RVE. The current study investigates the influence of the volume fraction of voids present in the matrix and their distribution throughout the RVE domain on the macroscale mechanical response. Material nonlinearity is considered for the matrix phase. Numerical assessments are performed to investigate the influence of the volume fraction and the distribution of the voids on the macroscopic response.