钽靶板在冲击下层裂过程的数值模拟

对平面冲击加载下延性金属钽的层裂行为开展了数值模拟研究。利用AUTODYN软件中的Lagrange与SPH求解模块,考察了3种本构模型Johnson-Cook、Steinberg-Cochran-Guinan与Zerilli-Armstrong的模拟结果,结合实验数据对模拟结果进行了验证;在此基础上,通过改变撞击速度与飞片厚度,获得了不同应变率下的自由面速度曲线,分析了不同应变率下的层裂特性。结果表明:在2.31×10⁴~5.40×10⁴s^?1应变率范围内,SPH求解器结合Steinberg-Cochran-Guinan本构模型的结果与实验数据具有较好的一致性;金属钽的层裂强度随拉伸应变率的增加而增大,在对数坐标系下近似呈线性关系;不同层裂强度计算方法得到的结果差异可达8%;随着拉伸应变率的增加,自由面速度回跳速率随之增长。最后,对自由面速度曲线中的特征参量的物理意义进行了解读。

Numerical Simulation of Spalling Process of Tantalum Target under Impacts

In this paper,the spallation characteristics of tantalum(Ta)under plate-impact loading are studied through numerical simulation.The feasibility and reliability of the Lagrange and smooth particle hydrodynamics(SPH)methods and several constitutive models(the Johnson-Cook,Steinberg-Cochran-Guinan and Zerilli-Armstrong model)are discussed.Comparison between the simulation results with experimental data,it is found that using the SPH method combined with the Steinberg-Cochran-Guinan constitutive model could produce the best consistency in the strain rate range from 2.31×10⁴ s^?1 to 5.40×10⁴ s^?1 for Ta.In addition,by changing the impact velocity and the thickness of the flyer,the free surface velocity curves under different strain rates are obtained,and the spalling characteristics under different strain rates are calculated and discussed.Characteristic parameters of spallation are calculated by using the free surface velocity data.The results have shown that the spalling strength of Ta increases with the strain rate,and is approximately linear in the logarithmic coordinate.Several computation methods of spall strength are considered in this work,and the difference between the results obtained by different methods are within the range of 8%.On the other side of the spectrum,the bounce rate of the free surface velocity increases with increasing strain rate.Finally,the physical meaning of the characteristic parameters in the free surface velocity curve is also discussed.