Abstract
The uniaxial compressive mechanical response of an epoxy, Epon 828/T-403, was experimentally, measured over a strain-rate range of 1.1 × 10-4 to 5.2 × 103 s-1. A modified split Hopkinson pressure bar was employed to apply dynamic compressive loading over a very short time of ∼ 0.2 millisecond, whereas an MTS was used to conduct quasi-static experiments at a duration of 0.2 to 2,000 seconds to determine strain-rate sensitivity. The experimental results show that the compressive strength of the epoxy increases with increasing strain rate until adiabatic heating offsets the strain-rate hardening. A constitutive model based on the Johnson–Cook model was constructed to describe the stress-strain behavior of the epoxy at the strain rates tested. A Ludwig equation was modified to model the stress-strain behavior at a reference strain rate, which included elastic deformation, a yield-like peak, and a strain-softening region. A hyperbolic tangent function provided a good description of the strain-rate effect. The material constants in this proposed model were determined using the experimental results.
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Chen, W., Zhou, B. Constitutive Behavior of Epon 828/T-403 at Various Strain Rates. Mechanics of Time-Dependent Materials 2, 103–111 (1998). https://doi.org/10.1023/A:1009866108965
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DOI: https://doi.org/10.1023/A:1009866108965