CL-20共晶及其复合材料结构与性能MD模拟研究

发布时间：2018-06-11 23:28

本文选题：CL-20/HMX共晶炸药 + CL-20/DNB共晶炸药　；参考：《南京理工大学》2015年硕士论文

【摘要】：本文采用分子动力学(MD)模拟方法,对CL-20/HMX与CL-20/DNB共晶及其复合体系,在COMPASS力场和不同温度下进行NPT-MD模拟。对于CL-20/HMX共晶及其复合体系,首先对ε-CL-20、β-HMX、CL-20/HMX混合与共晶体系进行不同温度下MD模拟。结果表明,随温度升高,ε-CL-20、CL-20/HMX混合与共晶体系中引发键(N-N02)最大键长Lmax显著增大,且Lmax值满足CL-20/HMX(共晶)CL-20/HMX(混合)ε-CL-20；混合与共晶体系内聚能密度CED、 CL-20与HMX之间结合能Ebind均随温度单调递减,并且CL-20/HMX共晶CED和Ebind均高于对应混合体系CED、Ebind值,表明共晶较简单混合体系更能显著降低体系感度、提高安全性和热力学稳定性。其主要归因于CL-20/HMX共晶体系不同组分之间存在强相互作用(氢键和vdW)。对相关函数g(r)揭示氢键作用主要由CL-20中H与HMX中O以及HMX中H与CL-20中O构成。与ε-CL-20和β-HMX相比,CL-20/HMX混合与共晶体系刚性减小、延展性均得到改善,但CL-20/HMX共晶仍属脆性,不能直接付诸实用,预示高聚物粘结炸药(PBXs)的必要性。随后分别添加Estane 5703和HTPB粘结剂构建PBXs模型,进行295 K MD模拟。发现含Estane 5703PBX稳定性和相容性更佳,g(r)揭示了粘结剂与基炸药界面相互作用的方式。添加少量粘结剂Estane 5703或HTPB,均使体系力学性能得到改善,并揭示其致钝机理。对于CL-20/DNB共晶及其复合体系,首先对ε-CL-20与DNB晶体、CL-20/DNB混合与共晶,进行不同温度下MD模拟研究,得出与CL-20/HMX共晶类似的结论,再次说明形成共晶要比简单将两种单体炸药混合更加钝感。与8-CL-20与DNB晶体相比,CL-20/DNB共晶与混合体系力学性能均得到改善。为提高CL-20/DNB共晶炸药的实际使用价值,改善其安全性和力学性能,首先以Lmax关联感度,预测CL-20/DNB共晶不同晶面的感度相对大小。随后选择HTPB和PEG作为粘结剂,沿其敏感晶面(001)面构建两种PBXs模型进行295 K MD模拟研究。结果表明PEG与共晶基炸药的相容性优于HTPB;与CL-20/DNB共晶相比,PBXs体系刚性减小,延展性增强,且粘结剂HTPB比PEG在改变共晶炸药力学性能进而致钝的效果较好。
[Abstract]:The NPT-MD simulation of CL-20 / HMX and CL-20 / DNB eutectic and its composite system is carried out by using molecular dynamics (MD) simulation under different temperature and force field. For CL-20 / HMX eutectic and its composite system, MD simulation of 蔚 -CL-20, 尾 -HMXCL-20 / HMXCL-20 / HMX mixed and eutectic system was carried out at different temperatures. The results show that with the increase of temperature, the maximum bond length Lmax of 蔚 -CL-20 / CL-20 / HMX and eutectic system increases significantly, and the Lmax value of CL-20 / HMX (mixed) 蔚 -CL-20; the binding energy Ebind between CL-20 and HMX decreases monotonously with the temperature. The CED and Ebind values of CL-20 / HMX eutectic are higher than those of the corresponding mixed system, which indicates that eutectic can significantly reduce the sensitivity of the system and improve the safety and thermodynamic stability compared with the simple mixed system. It is mainly attributed to the strong interaction between different components of CL-20 / HMX eutectic system (hydrogen bond and vdWN). The hydrogen bond is mainly composed of H and HMX in CL-20 and O in H and CL-20 in HMX. Compared with 蔚 -CL-20 and 尾 -HMX, the rigidity and ductility of CL-20 / HMX / HMX mixed and eutectic system decreased and the ductility was improved. However, CL-20 / HMX eutectic was still brittle and could not be directly applied, indicating the necessity of polymer bonded explosive (PBXs). Then the PBXs model was constructed by adding Estane 5703 and HTPB binder respectively and simulated with 295K MD. It is found that the better stability and compatibility of PBX containing Estane 5703 reveal the mode of interaction between binder and base explosive. The mechanical properties of the system were improved by adding a small amount of binder Estane 5703 or HTPB, and the mechanism of its obtuse was revealed. For CL-20 / DNB eutectic and its composite system, the mixing and eutectic of 蔚 -CL-20 and DNB crystal CL-20 / DNB are studied by MD simulation at different temperatures, and the results are similar to those of CL-20 / HMX eutectic. Again, the formation of eutectic is more obtuse than simply mixing two monomers. Compared with 8-CL-20 and DNB crystals, the mechanical properties of CL-20 / DNB eutectic and mixed systems are improved. In order to improve the practical use value of CL-20 / DNB eutectic explosive and improve its safety and mechanical properties, the relative sensitivity of CL-20 / DNB eutectic surface was predicted by using the Lmax correlation sensitivity. Then HTPB and PEG were selected as binders and two PBXs models were constructed along their sensitive crystal planes to simulate 295K MD. The results show that the compatibility of PEG with eutectic explosive is better than that of HTPB.The rigidity of PBXs system decreases and the ductility is enhanced compared with CL-20 / DNB eutectic system, and the binder HTPB is better than PEG in changing the mechanical properties of eutectic explosives and resulting in obtuse.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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