数值模拟是研究撞击坑形成过程的一种主要方法,尤其是认识撞击坑形成机制的重要手段。撞击坑形成过程数值模拟的基本原理是用离散方法描述物质在高速撞击作用下的运动及状态,在模拟中首先将物质与空间划分成离散的网格,在每一次迭代计算中逐步求解各个网格的形变、运动与状态改变的规律。牛顿运动定律、物质的连续体模型与热力学方程是撞击坑形成过程数值模拟的理论基础,牛顿运动定律以偏微分方程的形式贯穿在离散化的网格空间中,物质的连续体模型将物质的屈服强度与破裂、温度、孔隙、振动等联系起来,而热力学方程则通过其他热力学参数计算网格单元内物质的压强与物质所处的状态。
Numerical simulation is one of the main methods in impact crater formation study and an important means to understand its mechanism especially for large craters.The basic principle of numerical simulation of impact crater formation is to describe the material's motion and state under high velocity impact through computer code.The material and space are first divided into discrete meshes,whose deformation,motion and state will be calculated in each time step.Newton's Law of Motion,material constitutive model,and the equation of state are the theoretical basis in the numerical simulation of the crater formation.Newton's Law of Motion is implemented in the discrete meshes through partial differential equations,while the material constitutive model relates the yield strength to the damage,temperature,porosity,and vibration,and the equation of state is used to calculate the pressure within the meshes and the material state through other thermodynamic parameters.