Smoothed particle hydrodynamics (SPH) is adopted to simulate the peak impact load, the water entry process and the water entry characteristics of a re-entry capsule with the complex capsule motions modelled by a developed six degrees of freedom fluid-solid coupling model. Diffused particle distribution is developed and used in the simulations to decrease memory and computational cost. The results show that the six degrees of freedom model and diffused particle distribution are valid. The results obtained by the improved SPH method match well with experimental results, and the maximal impact load of the capsule may reach more than 10 G, even tens of G. In addition, the peak impact loads are significantly affected by the capsule vertical velocity, the capsule mass, and the pitch angle, while are slightly affected by the horizontal velocity. More concretely, the peak impact load increases with the increase of vertical velocity, and decreases with the increase of mass. However, there is no definite law between the peak load and the pitch angle. These results can provide a foundation for guiding capsule design.

采用光滑粒子流体动力学（SPH）来模拟峰值回弹载荷，入水过程和再入舱的入水特性，并通过已开发的六自由度流固耦合模型来模拟复杂的舱盖运动。开发了扩散粒子分布，并将其用于仿真中以减少内存和计算成本。结果表明，六自由度模型和扩散粒子分布是有效的。改进的SPH方法获得的结果与实验结果非常吻合，胶囊的最大冲击载荷可能会超过10 G，甚至数十G。此外，峰值冲击载荷会受到胶囊垂直速度的显着影响，胶囊的质量和俯仰角受水平速度的影响很小。更具体地，峰值冲击载荷随着垂直速度的增加而增加，而随着质量的增加而减小。但是，在峰值负载和俯仰角之间没有明确的定律。这些结果可为指导胶囊设计提供基础。