延性金属层裂模型比较

Comparison of different spall models for simulating spallation in ductile metals

在平面一维弹塑性流动有限差分计算程序中加入4种延性金属层裂模型,对平板撞击层裂实验进行数值模拟。结果表明:简单最大拉伸应力模型和简单损伤累积模型能定性反映层裂的物理现象,由于忽略损伤对本构的影响,计算结果和实验有偏差,但模型要求参数较少,对于一些精度要求不是很高的工程问题,可以采用;从材料损伤断裂物理本质出发,采用微损伤统计方法得到的NAG模型和封加波损伤度函数模型,能很好地再现实测的自由面速度剖面,数值计算结果与实验吻合很好。

By using one-dimensional finite different hydrodynamic code coupled with four spall models, spall in ductile metal has been studied. Numerical simulation results indicate that. （1）Cut-off model and simple damage accumulation model can qualitatively describe some physical essences of spall fracture, but remain apparent discrepancies from the experimental results due to the damage influence on the material properties being neglected; However, because of using a few parameters, they are still useful to solve engineering problems without considering higher precision. （2） NAG model and FJB damage degree function model based on statistical micro-damage mechanics have a good ability of description of the process of damage evolution, and the computed free-surface velocity profiles consist with the experimental measurements very well.