S580B钢中低应变率动态拉伸试验方法及本构表征研究

Dynamic Tension Methods and Constitutive Characterization of S580B Steel at Intermediate and Low Strain Rates

以S580B钢为研究对象,利用高速液压伺服材料试验机开展了其在中、低应变率范围的动态拉伸试验。提出了一种借助静态标定试验来间接测量动态载荷的方法,通过数字散斑相关方法测量应变场,获得了不同应变率下的真实应力-应变曲线,试验结果显示此材料具有明显的应变硬化效应和应变率敏感性。基于试验数据,采用Johnson-Cook模型拟合得到了S580B钢的动态本构方程,以其作为试验件有限元仿真的材料参数,仿真结果验证了拟合的动态本构方程能够较为准确地表征S580B钢的动态力学特性。

The dynamic tensile experiments of $580B at intermediate and low strain rates were developed with the high velocity hydraulic servo-testing machine. An indirect method of measuring dynamic load by aid of static calibration experiment was proposed, and the strain field was calculated with digital speckle correlation method. Therefore, the true stress-strain curves at different strain rates were obtained, and the results showed the material behaved apparent strain-hardening effect and strain rate sensitivity. The dynamic constitutive equation of $580B was fitted with Johnson-Cook model and the corresponding material parameters were applied to the finite element simulation of the test specimen, and the simulation result demonstrated the constitutive equation could exactly illustrate dynamic mechanical property of the material.