高能单质炸药力化学耦合机理的细微观试验和模型研究

Exploring the balance between high explosive safety and explosive output power is extremely challenging research topic in current energetic materials field. Based on mesoscopic physics mechanism, evaluation of the sensitivity of high explosives not only is required for safety use, but also help to precisely reflect the chemical reaction level during explosion stages. Initiation sensitivity of composite explosives depends strongly on the coupling process of mechanics and chemistry, which is influenced by its complicated microscopic structure. Single compound high explosive is the ideal material for fundamental mechanism study. Mechanics and chemical coupling responses are closely related to localization phenomenon at the meso and micro scales. Macro experiments were oriented to obtain the overall average energy output response, in which interaction between stress state and reaction path decomposition can not be revealed. To realize real-time observation of ignition-burning-explosion in small size single compound high explosives, this project proposed to establish dynamically loading test device equipped with optical microscope and electron microscopic analyzer. Researches on relationship between high precision image and temperature and pressure evolution can help to obtain heat generation and initiation information at the micro-meso scales. The experiments can offer critical conditions for ignition and combustion reaction level quantitatively for the given explosives. Through this project research, fundamental evidence at the microscale for investigating mechanics-chemical coupling mechanism can be obtained. This project will promot deep understanding of initiation mechanism and accurate quantitative prediction of sensitivity for energetic materials.

探索高能炸药安全性和爆炸威力之间的平衡，是当前含能材料领域极具有挑战性的研究课题。基于细观物理机制评价高能炸药的敏感性既是安全使用的需要，更可准确反映出爆炸过程中各阶段对应的反应等级。复合炸药起爆敏感性不仅受其复杂细观组成的影响，而且强烈地依赖于所填充单质炸药的力学和化学耦合过程。单质炸药是进行机理和基础试验研究的理想材料，其力化学耦合响应与细微观尺度局部化现象密切相关。宏观试验均着眼于获取整体的平均能量输出响应，无法揭示炸药受力状态与反应分解路径相互作用过程。本项目拟建动态加载和光学电子显微测试于一体的试验装置，实现小尺寸单质炸药点火-燃烧-爆炸的实时观测，研究高精确度图像与温度压力演化的关系，获得单质炸药细微观尺度上的热点生成和反应起爆信息，定量给出炸药点火临界条件及反应级别，为探究炸药力化学耦合机理提供细观尺度的试验依据，促进含能材料起爆机理深入理解及其感度的准确定量预测。

探索高能炸药安全性和爆炸威力之间的平衡，是当前含能材料领域极具挑战性的研究课题。项目基于多种热点机制对高能炸药建立力-化学细观模型，描述单质炸药在较宽范围的撞击加载下变形破坏及起爆响应。针对单质炸药分别从试验和细观计算两方面进行研究，通过对含能单晶HMX/RDX的纳米压痕试验，获得其各向异性力学性能参数，标定了力学本构模型参数；利用原子力显微镜（AFM）观测载荷-位移曲线出现的加载突进和卸载突退等单晶细微观破坏特征，确定了压痕周围产生径向或侧向裂纹的临界载荷；对炸药HMX和RDX单晶进行低速撞击试验，根据径向扩展速率、火焰传播速率、溅射速率对响应过程进行了定量化评价；研究了HMX和RDX单晶在未发生点火撞击条件下的破碎表征和理论分析，并且统计了碎片尺寸的分布状态，给出了不同落锤高度撞击的碎片分布规律，基于破碎分析开展了含能单晶的撞击点火机理，为发展感度预测理论模型提供了重要思路。通过设计轻气炮平板撞击试验，研究了HMX和RDX各向异性的力学响应，分析得到单晶塑性本构参数，建立了含能单晶各向异性本构，用于模拟PBX动态损伤失效过程及细观反应，对颗粒炸药动态加载的试验测试方法进行改进，解决单质颗粒炸药小尺寸样品取样的问题；完成了落锤动态加载及光学测试平台的建立，设计并加工了一套可用于单晶力学性能的动态压痕试验装置，对研究单质炸药细微观力学和化学响应机制的关联性和评价含能材料敏感性及安全性具有重要意义。该项目为探究炸药力化学耦合机理提供细观尺度的试验依据，对研究含能材料起爆机理，以及炸药感度的准确定量预测具有一定的指导意义。