不同晶粒度高纯铜层裂损伤演化的有限元模拟  

Numerical simulation on dynamic damage evolution of high pure copper with different grain sizes

作　　者：林茜 谢普初 胡建波[2] 张凤国[3] 王裴[3] 王永刚[1] Lin Qian;Xie Pu-Chu;Hu Jian-Bo;Zhang Feng-Guo;Wang Pei;Wang Yong-Gang(Key Laboratory of Impact and Safety Engineering,Ministry of Education of China,Ningbo University,Ningbo 315211,China;Key Laboratory of Shock Wave and Detonation Physics,Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621900,China;Institute of Applied Physics and Computational Mathematics,Beijing 100094,China)

机构地区：[1]宁波大学,冲击与安全工程教育部重点实验室,宁波315211 [2]中国工程物理研究院流体物理研究所,冲击波物理与爆轰物理重点实验室,绵阳621900 [3]北京应用物理与计算数学研究所,北京100094

出　　处：《物理学报》2021年第20期107-115,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11972202);国防基础科研科学挑战专题(批准号:TZ2018001)资助的课题。

摘　　要：采用Voronoi方法构建了50,130和200μm三种晶粒度的高纯铜靶板,在晶界处随机预制损伤成核点,建立了平板撞击高纯铜靶板的二维轴对称计算模型,研究了晶粒度和加载应力对高纯铜层裂宏观力学响应和细观损伤演化的影响.基于自由面速度剖面特征分析,揭示了晶粒度和加载应力幅值对Pull-back速度回跳点位置、速度回跳斜率及回跳幅值的影响规律,论证了层裂强度与损伤区拉伸应力峰值相对应本质上表征微损伤早期长大临界应力;基于损伤演化云图特征分析,讨论了长大和聚集过程中微孔洞周围局域化塑性应变场的演变,揭示了晶粒度和加载应力对微孔洞聚集和应力松弛行为的影响.计算结果再现了层裂实验中材料内部的微孔洞长大、聚集的细观物理过程,进一步揭示其与宏观力学响应之间的内禀关系,这对认识层裂损伤演化机制和理论模型构建具有重要的意义.High-purity(HP)copper targets with grain sizes of 50,130 and 200μm are constructed by using the Voronoi method.Damage nucleation points are randomly prefabricated at the grain boundaries.A twodimensional axisymmetric finite element model is established to simulate the spallation experiment of HP copper target.The effects of grain size and loading stress on the macro-mechanical response and meso-damage evolution of HP copper spallation are studied and compared with the relevant experimental results.Based on the analysis of free surface velocity profiles,the effects of grain size on the location of pull back velocity rebound point,velocity rebound slope and velocity rebound amplitude are revealed.It is demonstrated that the spalling strength corresponds to the peak value of tensile stress in the damage zone,which essentially represents the critical stress of micro damage nucleation or early growth.Based on the characteristic analysis of damage evolution nephogram,the evolution process of localized plastic strain field around the micro-voids in the growth and coalescence process is reproduced,and the strong dependence of micro-void coalescence behavior on grain size is clarified.The loading stress amplitude has little effect on the location of pull back velocity rebound point,but has a significant effect on the growth and coalescence behavior of micro-voids.The slope and amplitude of pull back velocity rebound increase with loading stress increasing,which is consistent with the relevant experimental result.With the increase of the loading stress,the micro-voids grow from independent growth to coalescence,thus forming spalling surface.The physical process of damage evolution determines the wave oscillation characteristics after the pull-back rebound point.The numerical simulation results reproduce the physical process of damage evolution and its influence on the macroscopic mechanical response,which is of great significance for further understanding spall damage evolution mechanism and theoretical model construction

关 键 词：层裂 晶粒度 数值模拟 损伤演化 

分 类 号：TG146.11[一般工业技术—材料科学与工程]