Characterization and modeling of strain rate hardening in natural-fiber-reinforced viscoplastic polymer

The effect of strain rate (ɛ·) on the mechanical properties of short‐hemp‐fiber‐reinforced High Density Polyethylene is characterized and modeled at different values of ɛ· and hemp fiber volume fraction (vf) under dry and wet conditions. Based on the experiments, a generalized comprehensive power law model is developed to predict the behavior of the mechanical properties as functions of vf, ɛ·, and moisture absorption. It is demonstrated that the developed model successes to accurately simulate the effects of vf, ɛ·, and moisture absorption on the mechanical properties of the natural‐fiber‐reinforced composites as well as the unreinforced polymer. POLYM. COMPOS., 35:2290–2296, 2014. © 2014 Society of Plastics Engineers