基于Johnson-Cook本构模型的高强度装甲钢动态力学性能参数标定及验证

具有高屈服强度的某装甲钢广泛应用于我国装甲车辆。为准确模拟该装甲钢的动态力学行为，开展基于Johnson-Cook（J-C）本构模型的动态本构参数标定及验证。采用万能材料试验机对该装甲钢进行不同温度下的准静态拉伸试验，同时采用分离式霍普金森压杆开展不同应变率下的压缩性能测试。基于实验数据和J-C本构模型，拟合得到该装甲钢的本构参数。基于轻气炮开展泡沫铝弹丸冲击均质梁的实验研究，分别采用J-C本构模型和理想弹塑性模型进行有限元仿真计算，并将冲击实验与数值结果进行对比分析。结果表明：该装甲钢具有应变率强化效应，且温度软化效应显著；采用J-C本构模型仿真的均质梁峰值挠度与试验结果的相对误差为1.7%~6.1%，残余挠度相对误差为0.6%~7.6%。

Calibration and Verification of Dynamic Mechanical Properties of High-strength Armored Steel Based on Johnson-Cook ConstitutiveModel

A specific type of armored steel with high yield strength has been widely used in China to improve the protection performance of armored vehicles. To numerically simulate the dynamic properties of the material，the material’s dynamic constitutive parameters based on the Johnson-Cook constitutive model are calibrated and verified through experiments. First，quasi-static mechanical properties of the armor steel are systematically measured using a universal material testing machine under temperatures ranging from room temperature to 550 ℃.The compression properties of the material are further measured at various strain rates using a separated Hopkinson pressure bar system. Second，based on the Johnson-Cook constitutive model，the measured dynamic properties of the armor steel are fitted to obtain the material’s constitutive parameters. Finally，a monolithic beam made of the armor steel is impacted by a aluminum foam projectile launched from a light-gas gun，and the test results are compared with finite element simulation results obtained using the constitutive parameters and the ideal elastic-plastic constitutive model. The results show that the armor steel demonstrates strong strain rate strengthening effect and thermal softening effect. The relative error between the peak deflection values of the monolithic beam obtained from J-C constitutive model simulation and experimental study is 1.7%-6.1%，and that for residual deflection is 0.6%-7.6%.