Effect of Strain Rate and Fiber Volume Fraction on the Mechanical Behavior of Kevlar/Glass Hybrid Composites

Abstract

This research presents an advanced micromechanical framework for analyzing the effects of fiber volume fraction (V_f) and strain rate on the mechanical behavior of Kevlar/glass hybrid composites under strain rate. The proposed model captures rate-dependent failure mechanisms through the integration of Mori–Tanaka homogenization, a strain-rate-enhanced Hashin failure criterion, and constitutive formulations inspired by Johnson–Cook theory to simulate the evolution of stress, damage, and stiffness degradation across a wide range of loading rates. Emphasis is placed on the nonlinear coupling between V_f and strain rate (ε̇), revealing that increases in V_f significantly enhance both ultimate tensile strength (UTS) and stiffness, especially at fiber-aligned orientations (0°), where load transfer efficiency is maximized. Nevertheless, elevated V_f and ε̇ values correlate with a decline in failure strain, suggesting a transition toward more brittle failure modes. The model further identifies optimal V_f and strain rate configurations for maximizing energy absorption and maintaining structural integrity, offering critical insights for the design of impact-resistant hybrid composites. The consistency of the results within the theoretical framework (with deviations below 10%) supports the model’s predictive capability and establishes a robust structure–property–rate relationship for dynamic loading applications.