飞秒激光作用TATB的大尺寸分子动力学模拟  

Large-scale Molecular Dynamics Simulation of Femtosecond Laser Pulse Ablation on TATB

作　　者：伍俊英[1] 李钧剑 尚伊平 杨利军 陈朗[1] WU Junying;LI Junjian;SHANG Yiping;YANG Lijun;CHEN Lang(State Key Laboratory of Explosion Science and Safety Protection,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]北京理工大学爆炸科学与安全防护全国重点实验室,北京100081

出　　处：《兵工学报》2024年第7期2351-2363,共13页Acta Armamentarii

基　　金：爆炸科学与技术国家重点实验室开放基金项目(KFJJ20-04M)。

摘　　要：深入认识炸药在飞秒激光作用下的快速化学反应机制和热力响应特征,是发展飞秒激光加工炸药技术的基础。采用分子动力学方法,基于ReaxFF/lg反应力场,对不同飞秒激光能量作用于三氨基三硝基苯(TATB)炸药的过程进行亚微米级大尺寸反应分子动力学模拟,考虑炸药对飞秒激光的非线性吸收过程,分析炸药烧蚀去除机制、产物演化和热力响应规律。计算结果表明:不同强度的飞秒激光对TATB的烧蚀去除机制不同,当激光强度为6.79×10^(17) W/m^(2)时,TATB发生等离子体烧蚀,产物以小分子或等离子体为主;当激光强度为3.39×10^(17) W/m^(2)时,TATB发生不完全反应,产物以大分子或团簇为主;当激光强度为1.69×10^(17) W/m^(2)时,TATB发生光机械烧蚀,以完整分子形式被剥离去除;激光强度越高,烧蚀产物的温度和粒子速度越高,对烧蚀区周围的热力响应越严重,有引发点火的风险。A deeper understanding of the rapid chemical reaction mechanism and thermal response characteristics of explosivessubjected to femtosecond laser pulseablation is the basis for the development of femtosecond laser machining technology forexplosives.The large-scale reactive molecular dynamics simulations of 1,3,5-Triamino-2,4,6-trinitrobenzene(TATB)subjected to different femtosecond laser energiesare carried out based on ReaxFF/lg reaction force field.The non-linear absorption process of explosives to femtosecond laser pulse is considered,and the ablation mechanism,product evolution and thermal response of explosives are analyzed.The calculation results show that the ablation mechanisms of TATB are different underthe action ofdifferent intensity femtosecond lasers.When the laser intensity is 6.79×10^(17) W/m^(2),TATB is subjected toa plasma ablation,and the products are mainly small molecules.When the laser intensity is 3.39×10^(17) W/m^(2),TATB undergoes an incomplete reaction,and the products are mainly large molecules or clusters.When the laser intensity is 11.69×10^(17) W/m^(2),TATB is subjected to a photomechanical ablation,andthe explosives are removed in an intact original molecular structure.The higher the laser intensity is,the higher the temperature and particle velocity of ablation products are,and the more severe the thermal response around the ablation zone is,which could trigger the risk of ignition.

关 键 词：三氨基三硝基苯 飞秒激光 分子动力学计算 ReaxFF/lg反应力场 

分 类 号：TJ55[兵器科学与技术—军事化学与烟火技术]