TC4动态力学性能研究

Study on Plastic Constitutive Relationship Parameters of TC4 Titanium

材料的本构模型参量是结构冲击动力响应数值模拟的基础.本文运用静态实验机和SHB装置,对TC4在常温～750C°、应变率10-4 ～103s-1下的力学行为进行了研究,得到了相应的塑性本构模型参量.通过Taylor撞击实验及其数值模拟对本构模型参量进行了验证,表明所得参量可较好描述冲击载荷作用下材料的塑性力学行为.

The quality of the material model is a key factor affecting the accuracy of results of a finite element simulation, espicially of the impact phenomenon. Dynamic mechanical behaviors of TC4 titanium were studied over the strain rate range from 10^-4 to 10^3 s^-1 and temperatures range from room temperature to 750℃ with a split Hopkinson pressure bar system and a static material test system. The parameters of Johnson-Cook plastic constitutive relationship which takes into account of the effect of strain, strain rate and temperature on plastic flow stress were obtained through these experiments. The Taylor impact experiment of impact velocity about 200 m/s was carried out. The corresponding numerical simulation was conducted with the explicit finite element code LS-DYNA. The parameters are validated through the comparison between the Taylor experiment with its simulation. The consistency between experimental observation and numerical simulation indicates that the parameters obtained have the ability to describe the plastic behavior of TC4 titanium under high speed deformation.