高能脉冲X射线辐照材料时,能量沉积会使材料表层发生气化,并在材料内部形成高压热击波.目前一般采用差分方法对高压热击波过程进行数值模拟.文章尝试采用光滑粒子流体动力学(SPH)方法对X射线辐照材料进行数值模拟,由于材料表层的气化膨胀所致,膨胀后的粒子体积是原来的几十倍甚至上百倍,产生粒子大变形的粒子穿透现象；分析了产生粒子穿透现象的主要原因是气化边界处密度计算公式不合适所致,为此对密度计算公式进行了改进,并开展了基于改进密度计算公式的两种方法的数值模拟,两种方法的计算结果比较一致.%When high energy X ray irradiates materials, the energy will be deposited in the materials, the surface materials will gasify to generate a thermal shock wave inside the meterials; and the finite differential method is usually used for the numerical simulation of the thermal shock wave.In this paper, the method of the Smoothed Particle Hydrodynamics (SPH) method is used to simulate the process of X-ray irradiating materials, As the particles on the surface expand and gasify, the particle size is found to increase tens to hundreds times, and the particles would penetrate.This is caused by the computational formula for the density, which is shown as inappropriate, so this paper abandons the density equation in the SPH method and uses a new formula for calculating the density, and satisfactory results identical with those of the differential method are obtained.
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