A comprehensive comparison of continuum damage mechanics, XFEM, and the phase-field method for microscopic modeling cracks in fiber-reinforced composites

This study presents a comprehensive investigation into the failure behavior of UD fiber-reinforced composites subjected to transverse tensile loading, using a micro-mechanical finite element modeling approach. Three advanced crack modeling techniques, continuum damage mechanics (CDM) based on crack band theory, the phase-field method (PFM), and the extended finite element method (XFEM), were implemented at the micro-scale to simulate crack initiation and propagation. A representative volume element (RVE) of a glass fiber-reinforced polymer (GFRP) composite was constructed with periodic boundary conditions, and both the PFM and cohesive zone modelling approaches were employed to simulate failure at the fiber–matrix interface. For the first time, all three prominent damage models were incorporated into a single, consistent micromechanical framework, enabling a direct and systematic comparison of their predictive capabilities, computational performance, and sensitivity to mesh type and interfacial properties. This unified platform allows for comprehensive assessment and offers practical insights into the appropriate selection of damage modeling techniques for micromechanical simulations of composite materials. This micromechanical modeling strategy offers a powerful virtual testing environment that enables early-stage, high-fidelity predictions of composite failure behavior that can significantly reduce the need for costly and time-consuming experimental campaigns. The framework was also used to investigate the influence of microstructural features, such as debonding failure model, fiber distribution, radius, volume fraction, and RVE size, on stress concentrations and failure progression. This modeling strategy provides critical insights into the interplay between composite microstructure and failure response, supporting the informed design of damage-tolerant composites. • Systematic comparison of three crack modeling approaches, CDM, XFEM, and PFM, for predicting the post-peak behavior of UD composites. • Evaluation of the strengths and limitations of each method in capturing crack patterns and post-peak response. • Comparison of CZM and PFM for interface failure modeling with respect to mesh sensitivity and result accuracy. • Study of fiber radius, volume fraction, and clustering effects on composite failure behavior using the PFM.