冲击加载下环三亚甲基三硝胺的初始动态响应及反应机理  

Initial dynamic response and reaction mechanism of cyclotrimethylenetrinitramine under shock loading

作　　者：彭亚晶[1] 孙爽 刘伟娜 刘宇辉[1] Peng Ya-Jing;Sun Shuang;Liu Wei-Na;Liu Yu-Hui(College of Physical Science and Technology,Bohai University,Jinzhou 121000,China)

机构地区：[1]渤海大学物理科学与技术学院,锦州121000

出　　处：《物理学报》2021年第15期292-300,共9页Acta Physica Sinica

基　　金：辽宁省高等学校创新人才支持计划(批准号:LR2019004);辽宁省自然科学基金(批准号:20180550510);辽宁省教育厅青年项目(批准号:LQ2019011,LQ2017007);辽宁省普通高等学校校际合作项目(批准号:XJXM2020005)资助的课题.

摘　　要：当前,对暴露于极端环境中的含能材料的相对安全性的关注日益增加.理解含能材料在冲击加载下的初始分解机理是探索新型高能顿感材料的基础.本文利用多尺度冲击技术(multi-scale shock technique,MSST)结合反应力场(ReaxFF)分子动力学的方法研究冲击加载下环三亚甲基三硝胺(RDX)的完美晶体和分子空位晶体的初始动态响应及反应机理,计算了可能参与反应的原子间径向分布函数,分析了不同冲击速度及分子空位缺陷对冲击加载过程的影响.结果表明:在冲击加载下,完美RDX晶体和空位RDX晶体的初始分解方式均为首先发生N-NO_(2)键断裂,随后是C-N键的断裂.此外,还可能会出现C-H键断裂,并有氢转移到硝基中的氧原子上形成HONO.随着冲击速度的增加,两种RDX晶体的化学键断裂数目增多,反应更强烈.分子空位缺陷的存在增强了N-NO_(2)的反应活性,使其更易发生断裂,进而加速空位RDX晶体的初始反应.At present,the relative safety of energetic materials exposed to extreme environments is concerned widely.Understanding the initial decomposition mechanism of energetic materials under impact loading is the basis for exploring new energetic materials with high energy and low sensitivity.In this paper,we study the initial dynamic response and reaction mechanism of perfect cyclotrimethylenetrinitramine(RDX)crystal and RDX crystal with a molecular vacancy defect under shock loading by using the multiscale shock technique(MSST)combined with reactive force field(ReaxFF)molecular dynamics method.The RDX perfect supercell and supercell containing a molecular vacancy are constructed to simulate the shock process by using the generalized gradient approximation method in density functional theory and Perdew-Burke-Ernzerhof functional.Before loading the shock wave,one NVE ensemble and Berendsen thermostat are used to control the RDX equilibrium process.A multi-scale impact compression is loaded along the crystal A direction.The initial temperature is 300 K and the initial pressure is set to be an atmospheric pressure.The radial distribution functions between main atoms are calculated,and the influences of shock velocity and molecular vacancy defect on shock loading process are analyzed.The evolution of N-NO_(2) bond and C-N bond with time in RDX perfect crystals and vacancy crystals under shock velocity of 11 km/s are given.As a result,the possible initial decomposition path of perfect RDX crystal and vacancy RDX crystal are the first fracture of N-NO_(2) bond,followed by the cleavage of C-N bond at small shock velocity.The initial reaction of the RDX crystal with a molecule vacancy is earlier than that of the perfect crystal,which indicates that the vacancy crystal is more sensitive to shock and more prone to decomposition.Furthermore,the fracture of C-H bond is possible after the initial cleavage of N-NO_(2) bond and C-N bond,and then the H atom is transferred to oxygen atom in nitro group,forming HONO.As the shock veloci

关 键 词：含能材料 多尺度冲击 分子动力学 空位缺陷 径向分布函数 

分 类 号：TQ560.1[化学工程—炸药化工]