Modeling of Constitutive Behavior for Epon 828/T-403 at High Strain Rates

Experimental results on the uniaxial compressive stress-strainbehavior of Epon 828/T-403 over a strain rate range from 1.1 × 10^–4 to 5.2 × 10³ s^–1were simulated using a viscoelastic viscoplastic constitutive modeldeveloped by Hasan and Boyce (1995). An optimal combination of materialparameters for the constitutive model was determined by curve-fittingthe experimental results. A comparison between the modeling andexperimental results shows that this model, with proper parameters, iscapable of capturing the strain-rate effects, as well as the typicalpolymeric compressive stress-strain behavior, of Epon 828/T-403, whichincludes the stages of linearly elastic, nonlinearly elastic, yield-like(peak) behavior, strain softening, and nearly perfect flow. For all thestress-strain behavior modeled over seven decades of strain rate span,the maximum error between modeling and experimental results is less than25%. The temperature increase induced by the dissipated plasticwork is also computed and found to be between 3 and8°C at these strain rates.