冲击载荷作用下PBX炸药损伤与点火反应耦合机理研究

The damage of the explosives and its influence to ignition performance is the key issue of the explosives safety. However, the micro-structural response in explosives is very complex, the coupling mechanism between the damage response and ignition reaction is still not clear enough. In order to establish the causation in relationship between the damage response and ignition reaction of the polymer bonbed explosive (PBX), the present project is carried out by the following aspects: (1) based on high speed synchrotron x-ray phase contrast imaging, the loading, testing and observation system of two different impact experiments are designed to acquire the relationships between the damage and temperature effect of the PBX sample, the critical condition of ignition. The damage modes and the ignition mechanisms of the PBX are studied in depth. (2) In the microscopic level, a cohesive finite element method (CFEM) is developed to describe the thermal–mechanical–chemical responses of the PBX under impact loading. We can gain the changes of the mechanical and thermal parameters. (3) In the macroscopic level, based on crack friction and pore collapse, a coupled model the damage response and ignition reaction is developed. The mechanical parameters and temperature will be obtained, which can be compared with the microscopic simulation results. The coupling mechanism of the damage and ignition reaction of PBX under impact loading is revealed. The project expects to gain original achievements in the coulped mechanisms of damage and ignition of the PBX, which will provide guidance to engineering applications such as PBX formula, structural design and safety evaluation.

炸药的损伤对其点火特性的影响是炸药安全性研究的核心问题。然而炸药细观结构响应复杂，对其损伤与点火反应耦合机理认识仍不够清楚。为建立PBX炸药冲击损伤与点火特性之间的关系，本项目针对以下问题开展研究：（1）设计两套加载、测试和观测实验系统，分别获取炸药损伤与温升效应的耦合信息、炸药发生点火的临界加载条件；（2）在细观层面，建立包含界面摩擦、应变率及化学反应项的内聚力模型，模拟冲击作用下PBX炸药的细观结构变化及热点形成过程，获取其力学、热学等参量的变化情况；（3）在宏观层面，考虑微裂纹摩擦和孔洞塌缩联合作用，选取与点火反应相关联的特征物理量，建立冲击损伤与点火反应耦合模型，并与细观模拟结果进行对比和验证，揭示冲击载荷作用下PBX炸药的损伤与点火反应耦合机理。本项目期望在PBX炸药冲击损伤与点火反应耦合机理认识方面获得原创性成果，将为PBX炸药配方、结构设计及安全性评价等工程应用提供理论指导。

炸药的损伤对其点火特性的影响是炸药安全性研究的核心问题。然而炸药细观结构响应复杂，对其损伤与点火反应耦合机理认识仍不够清楚。因此，本项目对PBX炸药冲击损伤与点火特性之间的关系进行了深入研究，取得了如下研究成果：（1）获取了冲击载荷作用下PBX炸药响应特性、损伤机制、炸药发生点火的临界加载条件以及点火过程；（2）建立了包含界面摩擦、应变率及化学反应项的内聚力模型，模拟了冲击作用下PBX炸药的细观结构变化及热点形成过程，研究了高应变率下PBX炸药韧脆转变机制、颗粒形貌对裂纹扩展的影响机制，获取了冲击载荷作用下PBX炸药力-热转变过程中的参量；（3）建立了PBX炸药动态损伤与点火耦合模型，研究了不同应力状态下细观微裂纹演化与PBX炸药宏观力学响应之间的内在联系，预报了多种应力状态下PBX炸药的动态力学响应，结合实验结果验证了理论模型的正确性，研究了不同生热机制引起的PBX炸药温升效应。. 本项目完成了研究内容，达到了预定研究目标。出版学术专著1部；发表国际期刊研究论文4篇，SCI检索，发表国内期刊论文2篇，其中1篇EI检索，参加国际、国内会议3次并作口头报告，在国内学术会议上作邀请报告1次。. 通过本项目研究揭示冲击载荷作用下PBX炸药的响应特性及损伤机制，建立了PBX炸药冲击损伤与点火耦合模型。为安全弹药装药设计、评估提供理论基础和手段，也为各军兵种弹药的安全使用和保障提供技术支撑。.