Abstract: Numerical simulation of Fluid-Structure Interaction (FSI) problems is one of the most important topics in computational fluid dynamics. Many numerical methods have been proposed for the FSI problems. Most of these numerical methods have been proposed for the FSI problems by using Eulerian approach in fluid medium and Lagrangian approach in solid medium. For example, the arbitrary Lagrangian Eulerian (ALE) method [1, 2] is a straight forward strategy for modeling FSI problems, but the ALE method is generally difficult and time consuming to track the moving interface, especially for the interface under large deformation conditions. So, purely Lagrangian method may be attractive for FSI problems because the capability of Lagrangian meshless methods can naturally handle the moving interface with large deformation and large motion of fluid. Due to the success application of FEM in solving structural dynamics and the convenience of SPH in simulating free-surface fluid dynamics, the FEM was coupled with SPH (FE-SPH) to investigate the FSI problems. The FE-SPH model was proposed by Attaway et al. to study a structure-structure impact problem [3]. The FE-SPH model has also been applied to fluid-structure impact problems by Vuyst et al. [4] and to free-surface flow interaction with elastic structures by Groenenboom and Cartwright [5], Fourey et al. [6] and Jones et al. [7]. Fourey et al. used ghost particle boundary for SPH and exerted the pressure calculating from SPH on the solid boundary of FEM. However, they didn’t discuss how to produce ghost particles coupling SPH with FEM for complex geometries.

In this paper, A new ghost particle method is proposed for arbitrary geometries which are discretized by elements. The ghost particles are produced based on the interceptive area of support domain of fluid particle kernel on the boundary. Then, the support domain is complete on interface between fluid and structure. We propose a scheme for dividing the interceptive area to produce ghost particles for SPH boundary coupled with FEM. The method proposed in this paper is different from other ghost particle methods, such as MBT, MVBP and eMVBP methods for complex geometries. In order to convenient coupling SPH with FEM, the interceptive area is divided to subset areas based on the corresponding segments of elements. The properties of ghost particles , such as density, mass and velocity, are defined by using the corresponding segments of elements to satisfy the hydrostatic condition and Cauchy boundary condition. Finally, the performance of the present method is discussed and validated by several numerical examples of FSI problems.