• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.115-127
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• 1997

A study to evaluate the seismic response of $\frac{1}{2}$-scaled liquid storage tank constructed in Hualien, is performed. And this study is to identify the liquid-structure-soil interaction by observed earthquake data ans analyzed results. After the calculation of soil impedance for the test site by SASSI code, 3-dimensional seismic response analysis is performed by BEM-FEM-Impedance Method with the consideration of liquid-structure-soil interaction when the tank is excited by real earthquake. The observed acceleration and hydrodynamic pressure are compared with the numerical results. This comparisons show good agreement in predominant frequency and maximum hydrodynamic pressure. And the free surface sloshing motion due to earthquake loadings is computed in time domain.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2147-2155
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• 2022

Nuclear safety-related underground liquid storage tanks, such as those used to store fuel for emergency diesel generators, are critical components for safety of hundreds of existing nuclear power plants (NPP) worldwide. Since most of those NPP will continue to operate for decades, a beyond design base (BDB) seismic screening of safety-related underground tanks in those NPP is beneficial and essential to public safety. The analytical methodology for buried tank subjected to seismic effect, including a BDB seismic evaluation, needs to consider both soil-structure and fluid-structure interaction effects. Comprehensive analysis of such a soil-structure-fluid system is costly and time consuming, often subjected to availability of state-of-art finite element tools. Simple, but practically and reasonably accurate techniques for seismic evaluation of underground liquid storage tanks have not been established. In this study, a mechanics based solution is proposed for the evaluation of a cylindrical underground liquid storage tank using hand calculation methods. For validation, a practical example of two underground diesel fuel tanks in an existing nuclear power plant is presented and application of the proposed method is confirmed by using published results of the computer-aided System for Analysis of Soil Structural Interaction (SASSI). The proposed approach provides an easy to use tool for BDB seismic assessment prior to making decision of applying more costly technique by owner of the nuclear facility.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.99-106
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• 1999

In this study a base-isolated liquid storage tank subjected to seismic ground motion is numerically simulated on frequency , domain considering three-dimensional liquid-structure-soil interaction. A hybrid formulation which combines the versatility of finite elements for tank structure and the efficiency of boundary elements for liquid and soil region is adopted for efficient modeling. The base-isolation system using the effective stiffness and damping ratio is also included in this formulation. in order to demonstrate the accuracy and validity of the developed solution the numerical results were compared with the reference solutions in each interaction problem. The effects of the liquid filling ratio and the stiffness of base-isolation system on the behavior of the liquid storage tanks are analyzed.

• Journal of Mechanical Science and Technology
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• 제20권6호
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• pp.795-805
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• 2006

Tuned Liquid damper and Tuned Liquid Column are kind of passive mechanical damper which relies on the sloshing of liquid in a rigid tank for suppressing structural vibrations. TLD and TLCD are attributable to several potential advantages - low costs ; easy to install in existing structures : effective even for small-amplitude vibrations. In this paper, the shaking table experiments were conducted to investigate the characteristics of water sloshing motion in TLD (rectangular, circular) and TLCD. The parameter obtained from the experiments were wave height, base shear force and energy dissipation. The shaking table experiments show that the liquid sloshing relies on amplitude of shaking table and frequency of tank. The TLCD was more effective control vibration than TLD.

• 한국해양공학회지
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• 제29권4호
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• pp.291-299
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• 2015

A variety of inner baffles are often installed to reduce liquid sloshing and prevent tank damage. In particular, a porous baffle has a distinct advantage in reducing sloshing by changing the natural periods and dissipating the wave energy in a tank. In model tests, porous baffles with five different porosities were installed vertically in a liquid tank under sway motion. The free surface elevations and pressures were measured using an image processing technique and a pressure gage for various combinations of baffle's porosity and submergence depth, and tank's amplitude and period. The experimental results were in good agreement with the analytic solutions (Cho, 2015), with the exception of a quantitative difference at resonant periods. The experimental results showed that the sloshing characteristics in a tank were closely dependent on both the porosity and submergence depth of the baffle, and the optimal porosity existed near P = 0.1275.

• Structural Engineering and Mechanics
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• 제57권5호
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• pp.877-895
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• 2016

This paper is concerned with the analytical derivation of natural sloshing frequencies of liquid in annular cylindrical tank and its verification by experiment. The whole liquid domain is divided into three simple sub-regions, and the region-wise linearized velocity potentials are derived by the separation of variables. Two sets of matrix equations for solving the natural sloshing frequencies are derived by enforcing the boundary conditions and the continuity conditions at the interfaces between sub-regions. In addition, the natural sloshing frequencies are measured by experiment and the numerical accuracy of the proposed analytical method is verified through the comparison between the analytical and experimental results. It is confirmed that the present analytical method provides the fundamental sloshing frequencies which are in an excellent agreement with the experiment. As well, the effects of the tank radial gap, the bottom flow gap and the liquid fill height on the fundamental sloshing frequency are parametrically investigated.

• KSTLE International Journal
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• 제7권2호
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• pp.45-50
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• 2006

In this paper, the leakage safety of prestressed concrete structure including the insulation panels has been analyzed using a finite element analysis just after a collapse of 9% nickel inner tank. This FEM study shows that the outer tank may contain the leaked cryogenic liquid for the time being until the primary pump in the inner tank transports stored cryogenic liquids to the nearest LNG storage tank before the outer tank is demolished. This means that the total tank thickness from the insulation panel to the outer tank system safely may retain the leaked cryogenic fluids. The FE computed results indicate that the current structure in a full containment tank is obviously enough to securing the leak-proof safety of the tank system with two primary pumps.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.178-183
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• 2020

A series of experiments covering lowest three natural frequencies of rolling coupled pitching were conducted to investigate liquid sloshing with low liquid depth. The test results show that the most violent liquid sloshing in rolling and pitching is located in the vicinity of the first order natural frequency (f1). When the excitation frequency of rolling and pitching is located between 0.98f1 and 1.113f1, roof-bursting phenomenon of liquid appeared, and the maximum impact pressure is at 1.09f1. When the external excitation frequency is at 1.113f1, the number of sloshing shocks decreases sharply. Furthermore, the space distribution of the impact pressure on the left bulkhead and the top bulkhead was analyzed. It is concluded that with low liquid filling, the impact load is greater near the free surface and the top of tank, and the impact position of the side bulkhead increases with the increasing of the frequency near the resonant frequency.

• 한국소음진동공학회논문집
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• 제23권7호
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• pp.662-668
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• 2013

In this paper, possibility of controlling motion of a floating structure using a tuned liquid damper (TLD) is numerically investigated. A TLD is a tank partially filled with liquid. Sloshing motion of liquid inside a tank is known to suppress movement of the tank subject to external excitations at specific frequency. The effects of sloshing phenomena inside a rectangular floating body on its surge motion are investigated by varying external excitation frequency. First, a grid-refinement study is carried out to ensure validity of grid independent numerical solutions using present numerical techniques. Then, surge motion of the floating body subjected to external wave is simulated for five different excitation frequencies of which the center frequency equals to the natural frequency of internal liquid sloshing. The normalized amplitudes of surge motion of the target floating body are compared according to the excitation frequency, for the cases with and without water inside the floating body. It is shown that the motion of the floating body can be minimized by matching the sloshing natural frequency to the excitation frequency.

• Computers and Concrete
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• 제14권4호
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• pp.369-385
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• 2014

In the existing method for analyzing the liquid tightness of the outer concrete tank in an emergency LNG spillage, the temperature variation over time inside the tank, and the concrete properties dependent on temperature and internal moisture content, have not been taken into account. In this study, the analyses for a typical LNG concrete tank subjected to thermal load due to spillage were performed with three different cases: the existing method was adopted in the first case, the transient temperature variation was considered in the second, and the temperature-moisture content dependent concrete properties were taken into account as well as the transient states of temperature in the third. The analysis results for deformation, compressive zone size, cracking, and stress of reinforcements were compared, and a discussion on the difference between the results obtained from the different analysis cases was made.