对高聚物粘结炸药（PBX）低速撞击点火预测是提升炸药甚至武器安全性的基础，低速撞击随机点火预测与炸药内部裂纹细观非均匀性密切相关，尚不能被传统材料本构模型所描述，这也是炸药低速撞击点火与炸药安全性研究的难点。本项目针对低速撞击炸药内部裂纹非均匀性的演化、能量局域化过程与炸药点火概率关联性等问题，以HMX基PBX炸药为研究对象，采用包括小角散射、Micro-CT和光学显微镜在内的无损检测技术，结合图像处理技术与统计分析方法，确定炸药初始裂纹的空间位置分布、尺寸和数密度等非均匀性分布特征。建立考虑初始裂纹非均匀性的PBX炸药宏细观材料本构模型，形成炸药随机点火预测方法，获得炸药Steven试验和Spigot试验等典型低速撞击点火的力-热响应特征，揭示PBX炸药随机点火宏细观机理，为炸药安全性的评估提供理论支撑和方法依据，对提高我国武器安全预测能力并制定安全策略具有实际价值。

The ignition prediction of polymer bonded explosives (PBXs) under low velocity impact is critical for the safety of explosives and weapons. The probabilistic ignition of PBXs under low velocity impact highly depends on initial crack heterogeneous distribution inside PBXs, and further could not be predicted based on traditional material constitutive models, which plays a critical role and a big challenge for the safety assessment of explosives..The evolution of initial heterogeneous cracks could result in energy localization related to the ignition. However, the relevant among the crack heterogeneous distribution, energy localization and the probabilistic ignition is still not clear. This project investigates the probabilistic ignition of HMX-based PBX under low velocity impact by means of testing techniques, material constitutive model and statistical method, with the aim of critical scientific issues as follows: (1) Non-destructive testing techniques, including small-angle x-ray scattering (SAXS), micro-CT and optical microscopy, are applied to analyze the feature of the spatial distribution, size, and density of the initial crack inside PBX by means of image processing techniques, and further to quantify the stochastic feature of the crack based on statistic method. (2) Considering the characteristic of initial heterogeneous cracks, a macro-microscopic material constitutive model is developed. (3) The method of the prediction of probabilistic ignition is proposed for revealing the mechanism of ignition in view of macro-microscopic level based on the mechanical-thermal response under the low velocity impact, such as Steven test and Spigot test..The methodology of the ignition prediction developed in this project offers a theoretical basis and methodological support for safety assessment of explosives. Furthermore, it probably offers a practical value for the improvement of the capability to predict the safety of weapons and the development of the safety strategy to use weapons.