Dynamic stress-strain response and yield behavior of polycarbonate

The uniaxial compression mechanical behavior of polycarbonate has been measured at strain rates ranging from 3.8×10~(-5)s~(-1) to 8200 s~(-1).The effect of strain rate on the yield stress of polycarbonate has been investigated at a wide range of strain rates.The results showed that at low strain rates,first an initial elastic response followed yielding,strain softening and then a dramatic strain hardening;at high strain rate,the softening dominating of stress strain curves disappeared and the yield stress and yield strain of polycarbonate increased with strain rates increasing.Competing mechanisms between strain softening and strain hardening of polycarbonate at high strain rates are discussed.Power law constitutive model for analysis of yield stress at a wide range of strain rates was proposed,which provides a better description relationship between yield stress and strain rates of polycarbonate from low to high strain rates.