Strain rate response of cross-linked polymer epoxies under uni-axial compression

Abstract

The strain rate responses of several cross-linked polymer epoxy materials were investigated under uni-axial compression at low to high strain rates. The properties of the epoxy were tailored through a variety of monomer choices including aromatic, which provide stiff, high glass transition structural materials, and aliphatic, which can form elastomers. The molecular weight and molecular weight distribution as well as the chemical functionality of the monomers can be varied to provide further control over the mechanical response. High rate experiments (greater than 1/sec rates) were conducted using a modified split-Hopkinson Pressure bar (SHPB) with pulse-shaping to ensure that the compressive loading of the specimen was at constant strain rate under dynamic stress equilibrium. In this paper, moduli and yield strengths as a function of strain-rate of the epoxies are presented and compared in an effort to understand the effect of the different tailoring to their mechanical response.