An improved Moving Particle Semi-implicit method and Finite Element Method (MPS-FEM) coupled approach is proposed for two-dimensional fluid-structure interaction problems in the present paper. The fluid subdomain is calculated by MPS method, while the structure subdomain is solved by FEM. Compared with the previous method, the structure subdomain is dispersed by a four-node plane element instead of beam element. Increasing available information including the variation of structural stresses can be obtained. Furthermore, an enhanced interpolation technique is applied for 2D FSI problems. Validation results of two benchmark FSI problems are illustrated, including dam-break flow through an elastic gate (Antoci et al.,2007) and free surface flow impacting on an elastic obstacle (Liao et al.,2015). The results obtained by improved MPS-FEM coupled method show good agreements with published experimental data as well as referenced numerical results. In addition, in the comparison between the improved method and previous ones, more precise and stabilized results can be observed.
Strong fluid-structure interactions together with violent free surface flows are frequent in hydrodynamics and ocean engineering. For instance, hydrodynamic slamming on marine vessels, tsunami impact on offshore structures, and sloshing in liquid containers. Such phenomena would produce tremendous pressure loads on the structure, even may cause considerable structural deformation. Hence, investigations of fluid-structure interaction problems with free surface present significant contributions to the field of ocean engineering. Moreover, the evaluations of the distribution of dynamic pressures and structural stresses are of substantial importance to marine structure design.
As we all know, laboratory experiments and theoretical researches on the field of FSI problems have some limitations due to its characteristics of obvious instantaneity and nonlinearity. Even so, a series of experiments related to FSI problems were performed. For example, Antoci et al. (2007) conducted a benchmark experiment of dam-break flow impacting on an elastic rubber gate, and structural deformation is measured. They also simulated this model by smoothed particle hydrodynamics (SPH) and a good agreement has been obtained compared with experimental data. Idelsohn et al. (2008) carried out a series of tests on rolling tank sloshing with an elastic baffle, includes hanging elastic beam with shallow water, clamped elastic beam immersed in shallow oil and deep oil, through experiment and numerical simulation, respectively. The numerical results based on particle finite element method (PFEM) consist with experimental data. Liao et al. (2015) investigated the phenomenon of free surface flow impacting on an elastic obstacle by experiment as well as numerical simulation based on coupled FDM-FEM method. Comparisons between experimental observations and numerical results were done to validate their numerical method.
