Analytical Constitutive Model For Stress - Strain Curves Of Pmma At Different Strain Rates

A simple equation has been proposed to describe the secant part of the stress-strain curves. This equation based on the stress and strain at the peak point. The unknown parameters of this equation were calculated by applying some conditions at three main points on the stress - strain curve. For the case of uniaxial compression loading of polymethelmethacrylate (PMMA) at different strain rates, it was found that the stress at the peak point and the strain at the beginning of the work hardening are related to the strain rate as exponential functions, whereas the inflection stress is linearly related to the peak stress. The equation proposed here was found to correlate well experimental data.