Abstract:Due to the peculiarity of mechanical behavior for titanium alloy under impact loading

its thermo viscoplasticity under high strain rate and the quantitative relation of temperature stress reduction and thermo viscoplasticity dissipation cannot be described by the classical Johnson-Cook model perfectly.In order to solve this problem

a modified Johnson-Cook model which expressed the functional relationship of temperature stress reduction about strain rate and thermo viscoplasticity dissipation was proposed

and all the parameters could be easily determined by the local search optimization algorithm taking least squares method as the object function.Finally

by the increment equations of the modified Johnson-Cook model derived under conditions of strain control

the dynamic true stress-strain curves for Ti-6Al-4V titanium alloy under different strain rates and temperatures could be drawn.The results of model analysis were verified by the results of experiments from reference. The modified Johnson-Cook model and the fast simulation method studied have reference value for other titanium materials.