• Transactions of the KSME C: Technology and Education
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• v.3 no.3
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• pp.193-199
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• 2015

Sloshing of LNG cargo can cause high impact loads on the supporting and containing structures. This is particularly critical for membrane-type tanks since these will have flat surfaces and corner regions which can lead to increased peak pressures for sloshing impacts. The membrane-type containment system is much more flexible compared to the steel hull structure. As a result, fluid-structure interaction plays an important role in the structural analysis of the containment system under sloshing load. This study is based on the direct calculation method of applying sloshing loads to the KC-1 basic insulation system using finite element analysis. The structural analysis of KC-1 basic insulation system considers the dashpot as fluid-structure interaction between liquid cargo and the LNG containment system. The maximum stress of the polyurethane form for KC-1 insulation system is 1.5 times lower than one without dashpot.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.4
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• pp.71-82
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• 1999

An axisymmetric shell element which includes the effects of the meridional and circumferential cable prestresses is developed. The fluid-structure interaction is expressed as added mass effect which is in proportion to the acceleration of the structure in interface surface. The added mass is obtained by using finite element method under the assumption that the fluid is invicid, incompressible and irrotational. It is coded for personal computer by the maximum use of axisymmetic properties and the dynamic analysis are performed under seismic exitations. A ring element makes the characteristics of the axisymmetric shell to be fully utilized. The elgenvalue solutons under the initial prestresses and the internal fluid are well agreed with the exact solutions and references by using under 20 elements. The eigenvalues are decreased along the increasing the height of internal fluid and these effects are dominant under the lower wave numbers. The results of the seismic analysis show that the radial deflection under the meridional prestress is a little larger than that under the circumferential prestress.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.132-137
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• 2001

This paper presents a method of seismic analysis for a 2-D fluid-structure-soil interaction systems. With this method, the fluid can be modeled by spurious free 4-node displacement-based fluid elements which use rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and the near-field soil are discretized by the standard 2-D finite elements, while the unbounded far-field soil is represented by the dynamic infinite elements in the frequency domain. Since this method directly models the fluid-structure-soil interaction systems, it can be applied to the dynamic analysis of a 2-D liquid storage structure with complex geometry. Finally, results of seismic analyses are presented for a spent fuel storage tank embedded in a layered half-space and a massive concrete dam on a layered half-space.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1143-1148
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• 2002

This paper analyses the transient response of a spherical elastic shell located near fee surface and impinged by spherical step-exponential acoustic shock waves. The problem is solved through extension of a method (Huang, 1969) previously formulated for the excitation in an infinite domain, which employs the classical separation of variables, series solutions, and Laplace transform technique The effect of the free surface reflection is taken into account using the image source method. The reflection of the incident wave has been treated by the same image formulation. If the reflection of the pressure field scattered and radiated by the shell is considered, the problem becomes that of multiple scattering by two spheres. However, this is in general negligible considering errors inherent from other sources and that the scattered and radiated pressure waves emanating from the shell are small. Thus, the problem is reduced to that of a structure immersed in an infinite fluid and impinged upon the origin and the image incident.

• Journal of Ocean Engineering and Technology
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• v.6 no.2
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• pp.46-54
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• 1992

In this paper, behavior of rectangular storage structures under earthquake loadings are investigated. Linear sloshing is assumed in this study. The effect of the wall flexibility is considered. Eulerian and lagrangian approaches are presented. The Eulerian approach is carried out by solving the boundary value problem for the fluid motion. In the lagrangian approach, the fluid as well as the storage structure is modelled by the finite element method. The fluid region is discretized by using fluid elements. The (1 $\times$ 1)-reduced integration is carried out for constructing the stiffness matrices of the fluid elements. Seismic analysis of the coupled system is carried out by the response spectra method. The numerical results show that the fluid forces on the wall obtained by two approaches are in good agreements. By including the effect of the wall flexibility, the forces due to fluid motion can be increased very significantly.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1033-1042
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• 1994

Dynamic behavior of flexible rectangular liquid containers is analyzed by a two-dimensional coupled boundary element-finite element method. The irrotational motion of inviscid and incompressible ideal fluid is modeled by boundary elements and the motion of structure by finite elements. A singularity free integral formulation is employed for the implementation of boundary element method. Coupling is performed by using compatibility and equilibrium conditions along the interface between the fluid and structure. The fluid-structure interaction effects are reflected into the coupled equation of motion as added fluid mass matrix and sloshing stiffness matrix. By solving the eigen-problem for the coupled equation of motion, natural frequencies and mode shapes of coupled system are obtained. The free surface sloshing motion and hydrodynamic pressure developed in a flexible rectangular container due to horizontal and vertical ground motions are computed in time domain.

• Journal of Korean Society of Steel Construction
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• v.21 no.2
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• pp.175-181
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• 2009

An intelligent control technique using a neural network is proposed for offshore structures exposed to sea-bed earthquakes. Fluid-structure interaction effect was considered in developing controller and a training algorithm for the neural network is presented. In the numerical example, the performance of the proposed neural network controller was compared with that of a passive controller and uncontrolled structures. Based on the example, it can be concluded that the proposed neuro-control scheme can be used for offshore structures with nonlinear characteristics due to its interaction with fluid.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.684-685
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• 2013

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.97-105
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• 2011

In rivers and streams, biofilms are thin layers of greenish-brown slime attached to rocks, plants, and other surfaces. Biofilms play key roles in primary production and cycling of nutrients, water quality remediation, suspended sediment removal, and energy flow to higher trophic levels. In the present study, we developed a two-dimensional cellular automata model to simulate mixed biofilms of toxin-sensitive and toxin-producing species in hydrodynamic flow. The flow was generated by a stochastic process for uniform flow and by using the Navier-Stokes equation for non-uniform flow. Minimized local rules governing reproduction and mortality of the species were executed in the self-organizing processes to elucidate interactions between toxin-producing and toxin-sensitive species in competition over nutrients. We briefly discuss the morphology of the simulated biofilm under different flow conditions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.8
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• pp.793-799
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• 2015

In this research, we study the propagation of longitudinal and transverse waves through a metal rod including a liquid layer using computational and experimental analyses. The propagation characteristics of longitudinal and transverse waves obtained by the computational and experimental analyses were consistent with the wave propagation theory for both cases, that is, the homogeneous metal rod and the metal rod including a liquid layer. The fluid-structure interaction modeling technique developed for the computational wave propagation analysis in this research can be applied to the more complex structures including solid-liquid interfaces.