基于SPH与FEM的结构入水分析方法

建立基于光滑粒子动力学（smoothed particle hydrodynamics, SPH）、有限元法（finite element method, FEM）和无反射边界耦合的结构入水分析方法，将无限水域利用无反射边界条件截断成有限水域，将有限水域分为流体变形大的SPH区域、流体变形小的FEM区域和声学流体FEM区域，结构用FEM离散。采用通用接触算法模拟SPH与FEM的耦合，采用声固耦合方法处理FEM区域之间的耦合，建立流固耦合的SPH FEM分析方法。该方法结合SPH模拟大变形的优点和FEM的高效性，可实现含自由液面变形、液体飞溅和无限水域等特点的流固耦合问题的模拟，为结构入水分析缩小离散区域、降低自由度和SPH粒子数等提供一种有效的分析方法。

Structure water entry analysis method based on SPH and FEM

A structure water entry analysis method based on smoothed particle hydrodynamics(SPH), finite element method(FEM) and non reflective boundary coupling is presented. The non reflective boundary condition is used to cut off an infinite water domain into a bounded water domain. The bounded water domain is divided into three domains, which are the SPH domain with large fluid deformation, FEM domain with small fluid deformation and acoustic fluid FEM domain. The structure is discretized by FEM. The coupling between SPH and FEM is modeled by general contact algorithm, and the coupling between FEM domains is modeled by acoustic structure coupling method. The SPH FEM coupling analysis method is proposed for fluid structure coupling problems. This method combines the advantages of SPH simulation for large deformation and high efficiency of FEM, and the fluid structure coupling problems is simulated on the deformation of free surface, fluid splash and infinite water domain, and so on. An efficient analysis method for structure water entry analysis is provided, which can reduce the discretization domain, the degrees of freedom and the SPH particle number.