摘要
用分子动力学方法,在295K NVT系综和COMPASS力场下,对环四甲撑四硝胺(HMX)晶体和F2311沿HMX(001),(010)和(100)晶面所构成PBXs模型的力学性能进行模拟研究.结果表明,加入F2311降低了HMX的刚性,增强了它的延展性.在HMX(100)面上添加F2311对提高体系的延展性较显著.为考察温度对力学性能的影响及其机理,在245～445K范围完成对HMX(100)/F2311PBX的MD模拟.力学分析表明,随温度增加HMX(100)/F2311的延展性呈抛物线变化规律,归因于F2311分子链的运动及其构象随温度的变化.
Molecular simulation was applied to investigate the mechanical properties of β-octahydro- 1,3,5,7-tetranitro-l,3,5,7-tetrazocine （HMX） crystals and the polymer-bonded explosives （PBXs） which were made from the HMX as a base and F2311 as a binder, in NVT ensemble using COMPASS force field. The PBXs＇ model was constituted by putting F2311 on crystal （001）, （010） and （100） surface respectively. At 295 K, the elastic constants and the effective moduli were calculated by statistic analysis mode. Cauchy pressure C12-C44 was also calculated. It was shown that the rigidity was weakened and the ductibility was improved by adding small amount of F2311, and the ductibility improvement was most obvious when F2311 was put on HMX （100） crystal surface. From the temperature 245 to 445 K with the increase step of 50 K, pure HMX crystals and HMX （100）／F2311 PBX were allowed to dynamically evolve. It is indicated that the mechanical properties of pure HMX crystals are unchanged because thermal effect of the volume is constrained by NVT ensemble. However, the ductibility of HMX （100）／F2311 PBX changes according to a parabola with increasing temperature due to the improvement of F2311 chain moving ability and the simultaneous increment of high energy conformation ratio in this molecular chain, i.e., the increment of the molecular chain rigidity.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2007年第17期1746-1750,共5页
Acta Chimica Sinica
基金
国家自然科学基金(Nos.10176012
20173028)
中国工程物理研究院重大基金(No.2004Z0503)资助项目.
