强冲击加载下延性金属卸载熔化损伤/破碎问题的物理建模及其应用  

Modelling of spall damage evolution and fragment distribution for melted metals under shock release

作　　者：张凤国[1] 刘军[1] 何安民[1] 赵福祺 王裴[1] Zhang Feng-Guo;Liu Jun;He An-Min;Zhao Fu-Qi;Wang Pei(Institute of Applied Physics and Computational Mathematics,Beijing 100094,China)

机构地区：[1]北京应用物理与计算数学研究所,北京100094

出　　处：《物理学报》2022年第24期278-286,共9页Acta Physica Sinica

基　　金：科学挑战专题(批准号:TZ2018001);国家自然科学基金(批准号:12271054)资助的课题。

摘　　要：强冲击下金属材料卸载熔化损伤/破碎问题是惯性约束聚变和武器工程等领域关注的关键问题之一,基于强冲击金属材料卸载熔化状态下损伤演化过程的特点以及已有的研究,本工作聚焦于解析熔融状态下材料内部孔洞分布特征的演化规律,明确损伤演化中后期的孔洞汇合模式,并给出相应的孔洞汇合判据,揭示惯性效应、温度效应以及孔洞汇合对损伤发展和孔洞分布特征变化的影响机理;建立损伤材料孔洞化失稳断裂与材料破碎颗粒度分布特性之间的关联,进而实现金属材料卸载熔化损伤/破碎全过程的物理描述.与现有的物理模型相比,采用新给出的物理模型计算得到的材料卸载熔化损伤/破碎颗粒度分布结果更接近实验回收统计结果.研究成果不仅加深强加载下材料动态损伤演化/破碎机理的物理认识,提升工程结构以及内爆过程材料动态破坏精细化数值模拟结果的置信度,也可以为结构设计优化和性能评估提供物理支持.A strong shock-wave,produced by plate impact,explosive detonation or laser irradiation,can induce metal materials to melt.Reflection of the triangular pressure wave from the free surface generates a strong tensile stress in the liquid state,resulting in the creation of an expanding cloud of liquid debris.This phenomenon is called micro-spalling.The understanding of spall damage evolution and dynamic fragmentation of melted metal under shockwave loading and subsequent releasing is an issue of considerable importance for both basic and applied science,to predict the evolution of engineering structures subjected to explosive detonation in implosive dynamics or inertial confinement fusion,the latter involving high energy laser irradiation of thin metallic shells.For dynamic failure processes,spall fracture in solid material has been extensively studied for many years,while scarce data can be found about how such a phenomenon can evolve after being melted partially or fully when being compressed or released.In this paper,by studying the physical laws of void evolution in melted metals,we expect to reveal the mode and criterion of void coalescence,inertial and temperature effects on void distribution and evolution,and the relationship between fragment distribution and characteristics of breakup of damaged material.According to these physical laws,we can develop theoretical model to describe the damage evolution and fragment distribution of metal that melts when shock releases.This model is implemented as a failure criterion in a one-dimensional hydrocode.The experimental results and computational results are in fairly good agreement with each other.Some discrepancies are explained by using both experimental uncertainties and model limitations which are carefully pointed out and discussed.We believe that these results can deepen our physical understanding of the damage evolutions of metals and improve the credibility of numerical simulation on the damage and fragmentation of materials under implosive loading.

关 键 词：层裂损伤 卸载熔化 孔洞汇合 破碎颗粒度 物理描述 

分 类 号：O347.3[理学—固体力学] TG14[理学—力学]