RDX杂质对HMX性能影响的分子动力学研究

为了研究奥克托今(HMX)制备过程中产生的黑索今(RDX)杂质对HMX性能的影响,分别建立了掺杂率为4.17%、8.33%、12.50%和16.67%的四种HMX模型。采用分子动力学方法,计算得到了不同模型的键连双原子作用能、内聚能密度、溶度参数、爆轰参数与力学参数,并与纯HMX相关性能参数进行了比较,结果表明,RDX掺杂缺陷导致炸药的键连双原子作用能和内聚能密度减小,减小幅度分别为9.53～36.36 kJ·mol~(-1),0.028～0.135 kJ·cm~(-3);受RDX掺杂缺陷的影响,HMX与氟橡胶(F_(2311))的溶度参数的差值减小,减小幅度为0.51～2.32 J1/2·cm~(-3/2),其密度、爆速和爆压减小幅度分别为1.12%～5.59%、0.84%～4.19%和2.27%～11.14%,爆热略有轻微上升,可忽略;RDX掺杂缺陷还导致HMX的弹性模量、体积模量和剪切模量降低,而柯西压以及体积模量与剪切模量的比值上升,其变化幅度分别为1.04～3.63 GPa、0.58～1.73 GPa、0.42～1.45 GPa、0.35～2.69 GPa和0.11～0.64。这说明,随着RDX掺杂缺陷浓度增大,HMX炸药的安全性能降低、爆轰性能下降、力学性能变差、与F_(2311)的相容性变好。

Molecular Dynamics Study on Effects of RDX Dopants on Properties of HMX

To investigate the effect of hexogen(RDX)dopants produced during the preparation of octogen(HMX)on properties of HMX, four kinds of HMX models of doping rate as 4.17%, 8.33%, 12.50% and 16.67% were established. Molecular dynamic method was used to calculate the interaction energy of trigger bond, cohesive energy density, solubility parameter, detonation parameters and mechanical parameters of different models, and the results were compared with the related properties of pure HMX. Results show that RDX doping defect leads to the decrease of interaction energy of trigger bond and cohesive energy density, and the reduction amplitude is 9.53-36.36 kJ·mol^-1, 0.028-0.135 kJ·cm^-3, respectively. The difference between the solubility parameters of HMX explosives and F₂₃₁₁ decreases with the influence of RDX doping defect, and the reduction amplitude is 0.51-2.32. The decrease amplitude of density, detonation velocity, and detonation pressure are 1.12% -5.59%, 0.84% -4.19% and 2.27% -11.14%, respectively. The heat of detonation rises slightly, which is almost negligible.The RDX doping defect also leads to the decrease of elastic modulus, bulk modulus, and shear modulus of HMX, but Cauchy pressure, as well as the ratio of bulk modulus to shear modulus rises. The changes range is 1.04-3.63 GPa, 0.58-1.73 GPa, 0.42-1.45 GPa, 0.35-2.69 GPa, and 0.11-0.64, respectively. It reveals that with the increase of the concentration of RDX doping defects, the safety and detonation performance of HMX explosives decrease, the mechanical properties become worse, and the compatibility with F₂₃₁₁ becomes better.