水冰的超高速撞击成坑机理及损伤方程

Water ice is one of the most aboundant molecules in the outer Solar System. It is considered a main constituent material of many icy bodies as icy satellites, comets, and Kuiper belt objects. Impact in water ice is the most important physical process in that region. The purpose of this project is to study the cratering behavior of water ice under hypervelocity impact. To obtain the relationship between the crater characterristics and impact parameters, some hypervelocity impact experiments on water ice over the range 1 to 7 km/s would be performed using two stage light gas gun. Numerical modeling would be performed using Smooth Particle Hydrodynamic method, to capture the mechanical and material responses of water ice due to hypervelocity impact at above 10km/s, and to explore the cratering mecahnism. Dimensional analysis method would be used to establish the function between crater morphologies and impact conditions, thus getting the damage equations by fitting to the experimental and numerical data. Based on above steps, an extropolated prediction of impact craters on typical icy body would be presented. One of the most important features of this project is utilizing the facilities and methods of explosive and shock dynamic mechanics into planetary physics research. The project achievements have scientifically significant value to research on forming, evolution and surface geomorphology of icy bodies in the outer Solar System.

水冰在太阳系外围含量丰富，是许多冰冻天体如冰冻卫星、彗星和柯依伯带天体的主要成分。对水冰的撞击是太阳系外围区域的重要物理过程。本项目将对水冰的超高速撞击成坑行为开展研究。拟在二级轻气炮上开展水冰在1-7km/s速度范围的超高速撞击实验，获得水冰撞击成坑特征与撞击条件之间的依赖关系。同时，采用光滑粒子流体动力学方法对水冰在10km/s以上速度的撞击成坑过程进行模拟，获得水冰在超高速撞击下的力学和材料响应，探索水冰超高速撞击成坑机理。采用量纲分析方法建立水冰撞击坑特征与撞击条件的函数关系，通过对实验和数值模拟数据的拟合建立水冰的超高速撞击损伤方程。在此基础上，对典型冰冻天体撞击成坑问题进行外推分析。本项目的特色是采用爆炸与冲击动力学手段研究行星物理学问题，项目成果对太阳系外围冰冻天体的形成、演化及其表面地形学研究具有显著的应用价值。