Strain rate influence on nonlinear response of polymer matrix composites

In this article, influence of strain rate on nonlinear response of unidirectional fiber-reinforced composites is studied. The fibers are assumed to be periodic arrays in composite structures. By studying a representative volume element, a microscopic constitutive model for characterizing macro-mechanical response of polymer matrix composites is developed. Viscoplastic material parameters of polymer matrix are acquired by axial tension and pure shear experiment, and the proposed method is validated by experimental data. The results showed that mechanical behavior of composites, which is affected by strain rate, can be ignored in the linear stage of loading. Furthermore, with the increase in strain rate, stiffness behavior of composites tends to be stiffer at the stage of nonlinear deformation. POLYM. COMPOS., 36:800-810, 2015.