Strain Rate Effect on the Stiffness of Random Fiber Composites due to Matrix Cracking and Interfacial Debonding

Considering the wide applications of composite materials, it is necessary understand the dynamic effects of damage mechanisms, including matrix cracking and interfacial debonding, on the stiffness performance of these materials. Strain rates may have a significant effect on the dynamic behavior of composite materials subjected to dynamic loadings. In this study, a numerical approach with the finite element code ABAQUS is used to develop a failure criterion to express the effect of static and dynamic damage mechanisms on the composite’s stiffness under uniaxial tensile loading. A random epoxy/glass composite material is investigated under three strain rates: quasi-static, intermediate, and high, here 10⁻⁴, 1, and 200 s⁻¹, respectively. The results illustrate that the interfacial debonding increases as the strain rate increases in random epoxy/glass composite materials. At the same time, the normalized stiffness components exhibit different trends with strain rate increase due to their connection to matrix cracking or interfacial debonding.