MS16- -02

COMPSAFE2020

ASI-ISPH Partitioned Coupling Analysis for Fluid-Structure Interaction
Hiroyuki Omura1, Naoto Mitsume2, Mitsuteru Asai3 and Daigoro Isobe4
12, 4

Graduate School of Science and Technology, University of Tsukuba
1-1-1 Tennodai, Tsukuba-shi, Ibaraki 305-8573, JAPANs2030186@s.tsukuba.ac.jp

Division of Engineering Mechanics and Energy, University of Tsukuba
1-1-1 Tennodai, Tsukuba-shi, Ibaraki 305-8573, JAPANmitsume@kz.tsukuba.ac.jp2, isobe@kz.tsukuba.ac.jp4
3

Department of Civil Engineering, Kyushu University744 Motooka, Nishi-ku, Fukuoka 819-0395, JAPANasai@doc.kyushu-u.ac.jp

In order to evaluate robustness of a building against tsunamis, it is necessary to consider theinteraction between building and tsunami. The Fluid-Structure Interaction (FSI) analysis isappropriate for this purpose. Most existing FSI methods are based on the finite element method(FEM) and formulated with presupposition that the structure models are discretized with thesolid elements. Therefore, there are few applications for large-scale cases such as tsunamibuilding interaction problems because of the huge computational cost.
In this research, we propose a partitioned FSI method based on the FEM using the beam elementthat is effective for analyses of framed structures such as buildings. The ASI-Gauss technique[1], which can efficiently compute yielding and fracture, is applied for the FEM. The particle
method is used as a fluid analysis scheme. Especially, the ISPH [2], which can obtain accuratepressure values and can conserve volumes well, is applied for the particle method. Besides, theExplicit Represented Polygon wall boundary model (ERP model) [3] is introduced into ISPHto evaluate fluid forces exerting on the boundary. We extend the ERP model to the implicit
particle method and the SPH because the original model was formulated for the Explicit MPS.
In addition, the representation of the Dirichlet condition for velocity by the ERP model isgeneralized to be applied to the moving boundary problems. The boundary shape of the beam
member is interpolated by using the coordinates of the nodes on both ends of the element, thepredefined sectional shape of the beam and the deformation computed by the structural analysis.
As described above, the fluid forces exerting on the beam elements are obtained from the fluidanalysis. These forces are converted into external forces for the structural analysis.
A hydrostatic pressure problem and a dam break problem with an elastic obstacle were solved
to verify. The numerical result showed that the proposed method can solve the fluid-structureinteraction problem with sufficient precision.
References[1] D. Isobe: Progressive Collapse Analysis of Structures: Numerical Codes and Applications,Elsevier, eBook ISBN: 9780128130421, Paperback ISBN: 9780128129753, 2017.
[2] M. Asai, et al.: A Stabilized Incompressible SPH Method by Relaxing the Density
Invariance Condition, Journal of Applied Mathematics, Vol. 2012, Article ID 139583, 2012.
[3] N. Mitsume, et al.: Explicitly represented polygon wall boundary model for the explicit
MPS method, Computational Particle Mechanics, Vol. 2, No. 1, pp. 73-89, 2015.

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