超高速撞击岩石相似规律及模型实验研究

The protective engineerings with rock nature defence layer are facing steadily increasing potential threat of hypervelocity weapons strike. The crater and penetration effects caused by hypervelocity impact have become the key and fundamental problems for the safety of significant protective engineerings and warhead designing. Exploring the crater and penetration similarity laws and discovering the essence in the physical and mechanical process have significant theoretical and practical value for damage effects research of hypervelocity weapons. The dimensional analysis will be employed. The micro-fracture, porosity, rate-dependent and intrinsic friction properties of rock will be considered and the influence relationship between these properties and crater will be explored, then the similarity laws of crater caused by spherical projectile impact at different boundary conditions will be discovered. Considering the time effect, the distribution relationship between volume energy and surface effects energy in the spallation process will be obtained, and the similarity law of crater edge spallation caused by spherical projectile will be explained. The intrinsic friction energy dissipation mechanism of fragmentized rock and the transformation law between heat and power of projectile materials will be taken into account, and the dimensionless groups will be set up. Lastly, the similarity laws of long-rod penetration with mass erosion and warhead bluntness will be found. With the similarity laws of different penetration states, the multistage penetration similarity law including different penetration states of long-rod will be established. With the dimensional analysis results, the scaling experiments will be put into practice to study the coupling relationship of different variables in crater and penetration effects, and the numerical simulation will be employed to compare and validate the similarity laws in larger scale.

以岩石为自然防护层的防护工程面临超高速武器打击的潜在威胁与日俱增，研究超高速撞击成坑和侵彻效应已成为重大工程安全防护与武器研发亟需解决的基础性课题。探索成坑和侵彻的相似规律，揭示物理力学过程本质，对超高速武器毁伤效应研究具有重要指导意义和实用价值。本项目拟采用量纲分析方法，考虑岩石含微裂纹、孔隙、应变率敏感、内摩擦等特性，探索各参量对成坑的影响关系，揭示不同边界条件下的球形弹撞击成坑相似关系；引入时间因素，厘清层裂过程中体积能与表面能的分配关系，阐明球形弹撞击成坑边缘层裂的相似关系；考虑破碎岩石内摩擦耗能及弹体材料热功转化机制，建立合理的无量纲组合，揭示质量磨蚀和头部钝化影响下长杆弹侵彻的相似规律；借鉴不同状态侵彻时长杆弹的相似关系，建立包含长杆弹不同状态的多阶段侵彻相似关系；根据量纲分析成果，设计模型实验，研究成坑和侵彻效应与各参量间的耦合关系，并在更大尺度上利用数值模拟对比验证。

以岩石为自然防护层的防护工程面临超高速武器打击的潜在威胁与日俱增，探索其撞击成坑和侵彻的相似规律，揭示物理力学过程本质，对超高速武器毁伤效应研究具有重要指导意义和实用价值。项目采用理论分析、模型实验及数值计算，研究了岩石等地质类材料超高速撞击机理及相似问题，主要工作及成果如下：. （1）围绕岩石类介质在球形弹撞击作用下的成坑效应、损伤深度开展了研究，得到了考虑冲击波传播和开坑过程的两阶段成坑模型和成坑深度计算方法，分析了靶体强度、含水率、孔隙率等参量对成坑效应影响，得到了相似关系。. （2）基于球形空腔膨胀模型和流体动力学模型，建立了刚性弹和侵蚀弹对砂土的超高速侵彻计算方法，得出了砂土可压缩性、弹体强度对侵彻的影响规律。. （3）引入压缩射流系数，利用伯努利方程，构建了刚性弹超高速撞击岩石的流体动力学模型，得到了侵彻深度与撞击速度、成坑形状与弹体形状、成坑体积与动力硬度等关系。. （4）考虑弹、靶破碎介质后向喷射，建立了侵蚀弹对岩石的超高速撞击工程计算模型，得到了侵彻深度、成坑半径变化规律。. （5）研究了不同速度下撞击问题的相似规律，薄板低速撞击时，冲击因子是决定临界破坏厚度的主要参量；刚性弹侵彻时，撞击因子、韧度因子和动力因子是控制侵彻效果的主要因素；超高速撞击中，侵彻深度与撞击速度呈对数关系，趋于“2/3模型律”。. （6）建立了超高速撞击中能量分配与地冲击份额计算方法，超高速撞击时绝大多数能量都转化成了动能和弹性压缩能，90%以上能量以地冲击形式在靶体中传播。. （7）阐明了A-T模型中靶体阻力项确定问题，Rt本质上是单位体积材料变形的塑性功，与动力硬度物理意义相同；提出了岩石类材料动力硬度测试方法，利用二级轻气炮试验得到了泡沫混凝土的动力硬度。. （8）利用二级轻气炮，区分球形弹与长杆弹开展了花岗岩超高速撞击模型试验，获得了撞击参数与成坑效应的影响规律。.成果能为超高速武器毁伤效应研究及工程防护提供支撑。