Strain-rate dependent micromechanical method to investigate the strength properties of glass/epoxy composites

The mechanical properties of glass/epoxy composites are sensitive to applied loading rates. In the present research, a strain-rate dependent micromechanical (SRDM) method is developed to predict the strength of unidirectional (UD) polymeric composites under various loading rates. In this paper, the Goldberg et al. model, as a strain rate dependent constitutive equation of polymers, has been combined with a micromechanics model (the bridging matrix method) to predict the strength of UD composites at arbitrary strain rates. In addition, the bridging matrix method is modified by using strain concentration factor to determine the transverse tensile and in-plane shear strengths of UD composites. To verify the proposed model, first the dynamic mechanical behavior of glass fibers and epoxy matrix were studied experimentally. Then, the predicted results are compared with the available experimental data of glass/epoxy composites. A comparison between predicted results and available experimental data for longitudinal tensile, transverse tensile and in-plane shear strengths of UD glass/epoxy composites under various strain rates shows the capability of the proposed novel model.