延性金属层裂自由面速度曲线特征多尺度模拟研究  

Multi-scale simulation study on characteristics of free surface velocity curve in ductile metal spallation

作　　者：王云天 曾祥国[1] 陈华燕[1] 杨鑫[2] 王放[3] 祁忠鹏 WANG Yuntian;ZENG Xiangguo;CHEN Huayan;YANG Xin;WANG Fang;QI Zhongpeng(MOE Key Laboratory of Deep Earth Science and Engineering,College of Architecture and Environment,Sichuan University,Chengdu 610065,Sichuan,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,Sichuan,China;School of Materials and Energy,Southwest University,Chongqing 400715,China)

机构地区：[1]四川大学建筑与环境学院,深地科学与工程教育部重点实验室,四川成都610065 [2]成都理工大学环境与土木工程学院,地质灾害防治与地质环境保护国家重点实验室,四川成都610059 [3]西南大学材料与能源学院,重庆400715

出　　处：《爆炸与冲击》2021年第8期136-150,共15页Explosion and Shock Waves

基　　金：北京应用物理与计算数学研究所计算物理重点实验室基金(Hxo2020-74)。

摘　　要：以延性金属钽为研究对象,对钽在平板撞击下的层裂行为进行了多尺度下的数值模拟研究,从微观视角对自由面速度曲线上的典型特征进行了新的解读。在宏观尺度,对比分析了光滑粒子流体动力学法(smootfied particle hydrodynamics,SPH)与Lagrange网格法以及几种本构模型的模拟结果及其适用性。通过与实验数据的对比表明,Steinberg-Cochran-Guinan本构模型在层裂模拟中与实验数据吻合较好,通过改变加载条件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自由面速度曲线中的典型特征。在微观尺度,采用分子动力学方法获得层裂区域内损伤演化情况,揭示了宏观尺度自由面速度曲线典型特征所蕴含的物理内涵。分析表明,层裂表现为材料内部微孔洞形核、长大和聚集的损伤演化过程,自由面速度曲线上的典型特征与层裂区域的损伤演化过程存在密切关联。Pullback信号是层裂区域内微孔洞形核的宏观表征;自由面速度曲线的下降幅值在一定程度上反映了微孔洞的形核条件,由此计算得到的层裂强度实际上是微孔洞的形核强度。此外,Pullback信号后的速度回跳速率反映了微损伤演化的速率。The spallation characteristics of ductile tantalum metal under planar plate impact was analyzed through a multiscale perspective.And the typical characteristics of the free-surface velocity curve on the macro-scale were interpreted from the micro-scale to reveal the physical meanings corresponding to these typical characteristics.On the macro-scale,the spallation behaviors of the ductile tantalum metal under planar-plate impact were numerically simulated through the smooth particle hydrodynamics(SPH)and Lagrange methods,and the free-surface velocity curves of the tantalum during spallation were obtained.In addition,the free-surface velocity curves obtained by the Johnson-Cook model,Steinberg-Cochran-Guinan model and Zerilli-Armstrong model were compared in the numerical simulations.Comparison with the experimental data shows that the Steinberg-Cochran-Guinan constitutive model has a better performance in the macro-level simulation.The freesurface velocity curves at different strain rates were obtained by changing the loading conditions,and the typical characteristics of the free-surface velocity curves at different strain rates were discussed.Results show that there is an exponential relationship between spall strength and strain rate,and the spall strength obtained from the simulation has a good agreement with the experimental data.On the micro-scale,the damage evolution in the spallation region was obtained by molecular dynamics simulation conducted in the LAMMPS software,and the loading strain rate was consistent with that on the macro-scale.The micro-scale simulation reveals the physical connotation of the typical characteristics of the macro-scale free-surface velocity curve.Micro-scale analysis shows that spallation is the response of damage evolution of nucleation,growth,and aggregation of voids.From the multi-scale perspective analysis,the typical characteristics on the free-surface velocity curve are closely related to the damage evolution in the spallation area:the pullback signal is a macroscopic respo

关 键 词：平板撞击 延性金属 多尺度模拟 自由面速度曲线 

分 类 号：O382.3[理学—流体力学]