Analytical Solution of Sloshing in a Cylindrical Tank with an Elastic Cover

Coupled fluid-structure is significant in many aspects of engineering applications such as aerospace fuel tanks, the seismic safety of storage tanks and tuned liquid dampers. Numerical investigation of the effects of thin plate cover over a cylindrical rigid fuel tank filled by an inviscid, irrotational, and incompressible fluid is investigated. Governing equations of fluid motion coupled by plate vibration are solved analytically. A parameter study on the natural frequency of coupled fluid-structure interaction is performed. The results show the non-dimensional natural frequency of coupled fluid-structure is a function of mass ratio, plate elasticity number and aspect ratio. This function is derived numerically for high aspect ratios which in companion with a semi-analytical could be used in the engineering design of liquid tanks with a cover plate.

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Numerical Analysis of the Dynamic Responses of Multistory Structures Equipped with Tuned Liquid Dampers Considering Fluid-Structure Interactions

The Open Construction and Building Technology Journal ◽

10.2174/1874836801913010289 ◽

2019 ◽

Vol 13 (1) ◽

pp. 289-300 ◽

Cited By ~ 2

Author(s):

Bui Pham Duc Tuong ◽

Phan Duc Huynh ◽

Tan-Trung Bui ◽

Vasilis Sarhosis

Keyword(s):

Fluid Structure Interaction ◽

Fluid Pressure ◽

Dynamic Responses ◽

Water Tank ◽

Tank Wall ◽

Tuned Liquid Damper ◽

Fluid Structure ◽

Structure Interaction ◽

Tuned Liquid Dampers ◽

Liquid Dampers

Aims: The paper analyzes the effectiveness of tuned liquid damper in controlling the vibration of high rise building. The new contribution is considering the fluid-structure interaction of a water tank as a Tuned Liquid Dampers (TLD). Background: Currently, buildings are being built higher and higher, which requires TLDs to be larger as well. Therefore, the fluid pressure acting on the tank wall is more significant. In previous studies of liquid sloshing in TLDs, researchers simply ignored the effect of liquid pressure acting on the tank walls by making the assumption that the tanks are rigid. Currently, the failure of a tank because of FSI occurs regularly, so this phenomenon cannot be ignored when designing the tanks in general and TLDs in particular. Objective: To investigate the thickness of the tank wall affect to the TLD mechanism. Method: Numerical method was used for this research. Results: A TLD could be easy to design; however one could not bypass the fluid-structure interaction by assuming the tank wall is rigid. Conclusion: This kind of damper is very good to mitigate the dynamic response of structrure.

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Tuned Liquid Damper Experiment Using Shaking Table

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.421.772 ◽

2013 ◽

Vol 421 ◽

pp. 772-777 ◽

Cited By ~ 1

Author(s):

Ki Pyo You ◽

Young Moon Kim ◽

Jang Youl You

Keyword(s):

Natural Frequency ◽

Damping Ratio ◽

Tall Buildings ◽

Excitation Amplitude ◽

Shaking Table ◽

Tuned Liquid Damper ◽

Tuned Liquid Dampers ◽

Liquid Dampers ◽

Water Tanks ◽

Wind Induced Vibration

The present study examines the characteristics of rectangular and circular tuned liquid dampers, which control wind-induced vibration in tall buildings, according to the natural frequency. The tuned liquid dampers (TLD) were of frequencies: 0.44Hz, 0.55Hz, 0.64Hz and 0.73Hz. The tuning feature of TLD water tanks was better in circular water tanks than in rectangular water tanks. Excitation amplitude affected the damping ratio based on energy dissipation capacity. At low excitation (below 5mm) and low natural frequency (0.44Hz), circular water tanks were advantageous over rectangular water tanks. However, at high excitation (over 5mm) and high natural frequency (over 0.55Hz), rectangular water tanks were advantageous over circular water tanks.

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Surge Response Control of FPSO Using Multiple Tuned Liquid Dampers: A Study on Effect of Multiple Frequencies in TLD

Volume 1: Offshore Technology; Offshore Geotechnics ◽

10.1115/omae2019-96062 ◽

2019 ◽

Cited By ~ 1

Author(s):

Saravanan Gurusamy ◽

Deepak Kumar

Keyword(s):

Crude Oil ◽

Natural Frequency ◽

Flexible Structures ◽

Deep Ocean ◽

Wave Loads ◽

Natural Period ◽

Response Control ◽

Tuned Liquid Dampers ◽

Oil Storage ◽

Liquid Dampers

Abstract Industries rely mostly on off-shore resources to fulfill the increase in demand for oil and gas. In general, for oil extraction and various other refinery processes, fixed or floating structures are being utilized. Floating Production Storage and Offloading (FPSO) system is one of the floating systems which have advantage of storing the crude oil and, if required, it can be easily moved to other places. Also, in deep Ocean where sub-sea pipeline infrastructures are often not possible and so the FPSOs give alternate option of storing and processing the crude oil. Being moored-systems, FPSOs are very flexible structures having high surge natural period and hence they may undergo larger surge displacement. Excessive displacement may cause damage for the riser system also it may affect the workability under extreme sea condition. Therefore, there is a need for investigating the issues of safety, efficiency and response control of FPSO systems under different sea-state conditions. Ocean wave loads on FPSO causes dynamic interaction between FPSO vessel and liquid in the oil storage containers. The liquid motion in containers disturbs the dynamics of the vessel significantly. Hence, it is essential to study the surge response control of FPSO in detail. An easy way to control the response is to use the existing cargo containers of FPSO as passive damping devices. If the natural frequency of liquid oscillation is tuned to the natural frequency of FPSO, these cargo tanks can act as Multiple Tuned Liquid Dampers (MTLDs). In case of simple linear model, Tuned liquid damper (TLD) can be idealized as a Single Degree of Freedom (SDOF) system, namely Tuned Mass Damper (TMD). The present study attempts to model a TLD using three different TMD systems to account the effects of shallow water sloshing.

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Numerical Study of Slat Screen Pattern Effect on Design Parameters of Tuned Liquid Dampers

Journal of Fluids Engineering ◽

10.1115/1.4026662 ◽

2014 ◽

Vol 136 (6) ◽

Cited By ~ 9

Author(s):

Morteza Marivani ◽

M. S. Hamed

Keyword(s):

Fluid Flow ◽

Numerical Investigation ◽

Natural Frequency ◽

Linear Theory ◽

Tall Buildings ◽

Design Parameters ◽

Damping Factor ◽

Tuned Liquid Dampers ◽

Solidity Ratio ◽

Liquid Dampers

Tuned liquid dampers (TLDs) are considered economical and effective dynamic vibration absorbers. They are increasingly being used to mitigate the dynamic resonant response of tall buildings and it is often designed to reduce the structure's acceleration at a serviceability limit state. Slat screens can increase the inherent damping factor of TLDs. They have been used as a common flow damping device in TLDs because of the simplicity of using them and also the ability to control their effects on the performance of a TLD. Two slat screens with the same solidity ratio and different patterns could have different effects on the TLD's performance. Many former numerical researches used the potential and linear theory as a base to describe the fluid flow behavior inside the TLD. The applicability of the linearized flow models was for the condition of the low amplitude of excitations. Under large excitation events such as high return period wind storms or earthquakes, the assumptions of linear theory are no longer valid. Moreover, in the linearized model, screens were modeled as a hydraulic resistance point as a function of the screen solidity ratio without the ability to consider the effect of screen pattern. In the present study, a numerical algorithm has been developed which can handle both the small and large amplitude of excitations. In this algorithm, the fluid flow through the screen is fully resolved and it can take into account the effect of the screen pattern on the TLD's performance. The major focus of this paper is to use this developed algorithm and conduct a numerical investigation to study the effects of the slat screen pattern on the inherent damping and natural frequency of the TLD, as the design parameters of the TLD. In this numerical investigation a selected TLD outfitted by different slat screens and interacted with the structure is exposed by both harmonic and random external excitations. The numerical results have been validated against experimental work. The effect of slat screen pattern on the damping effect and natural frequency of a TLD has been presented. Also in this study, two new parameters termed as slat ratio (SR) and effective solidity ratio (Seff) are presented to imply the physical significance of screen pattern.

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Multipoint Wave Measurement in Tuned Liquid Damper Using Laser Doppler Vibrometer and Stepwise Rotating Galvanometer Scanner

Sensors ◽

10.3390/s21248211 ◽

2021 ◽

Vol 21 (24) ◽

pp. 8211

Author(s):

Yoon-Soo Shin ◽

Junhee Kim

Keyword(s):

Natural Frequency ◽

Vibration Suppression ◽

Laser Doppler Vibrometer ◽

Laser Doppler ◽

Liquid Level ◽

Tuned Liquid Damper ◽

Tuned Liquid Dampers ◽

Liquid Dampers ◽

Tuning Frequency ◽

Galvanometer Scanner

Liquid dampers, such as tuned liquid dampers (TLDs), are employed to improve serviceability by reducing wind-affected building vibrations. In order to maximize the vibration suppression efficiency of the liquid damper, the tuning frequency of the liquid damper should match the natural frequency of the building. Experimental evaluation of the tuning frequency of a liquid damper performed in a factory prior to installation in a building is a critical task to ensure correct performance, and for this, multipoint measurement of the TLD is required. In this study, a novel liquid level measurement system combining Laser Doppler Vibrometer (LDV) and a stepwise rotating galvanometer scanner was developed to observe liquid sloshing in TLD. The proposed system can measure the liquid level at multiple points simultaneously with a single laser point. In the experimental phase, the liquid damper’s natural frequency and mode shape are experimentally evaluated utilizing the developed system. The performance of the proposed system was verified by comparison with the video sensing system.

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An Electrical Wave Height Measurement at Spatial Multipoint Locations in Liquid Dampers for Structural Vibration Mitigation

Journal of Sensors ◽

10.1155/2016/6874125 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9

Author(s):

Junhee Kim ◽

Seok-Jung Jang ◽

Kyung-Won Min

Keyword(s):

Electric Field ◽

Natural Frequency ◽

Vibration Suppression ◽

Vertical Motion ◽

Structural Vibration ◽

Height Measurement ◽

Tuned Liquid Dampers ◽

Liquid Height ◽

Liquid Dampers ◽

Tuning Frequency

Liquid dampers such as tuned liquid column dampers and tuned liquid dampers have been adopted to ensure serviceability of a vibratory building subjected to wind. In order to maximize efficiency of the vibration suppression, tuning frequency of the liquid dampers is supposed to be set to the first natural frequency of the building. Therefore, experimental evaluation of the natural frequency of liquid dampers is a primal factory task prior to their installation at the building. In this study, a novel liquid height measurement system based on variable resistance in an electric field is developed for observation of vertical motion of the liquid dampers. The proposed system can simultaneously measure the liquid height of multipoint locations in the electric field. In the experimental phase, natural frequency of the liquid dampers is experimentally evaluated utilizing the developed system. The performance of the proposed system is verified by comparison with the capacitive type wavemeter.

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Mechanical Stability of Hybrid Corrugated Sandwich Plates under Fluid-Structure-Thermal Coupling for Novel Thermal Protection Systems

Applied Sciences ◽

10.3390/app10082790 ◽

2020 ◽

Vol 10 (8) ◽

pp. 2790

Author(s):

Wenzheng Zhuang ◽

Chao Yang ◽

Zhigang Wu

Keyword(s):

Mechanical Stability ◽

Thermal Protection ◽

Element Model ◽

Parameter Study ◽

The Novel ◽

Thermal Coupling ◽

Mechanical Instability ◽

Fluid Structure ◽

Thermal Protection Systems ◽

Protection Systems

Hybrid corrugated sandwich (HCS) plates have become a promising candidate for novel thermal protection systems (TPS) due to their multi-functionality of load bearing and thermal protection. For hypersonic vehicles, the novel TPS that performs some structural functions is a potential method of saving weight, which is significant in reducing expensive design/manufacture cost. Considering the novel TPS exposed to severe thermal and aerodynamic environments, the mechanical stability of the HCS plates under fluid-structure-thermal coupling is crucial for preliminary design of the TPS. In this paper, an innovative layerwise finite element model of the HCS plates is presented, and coupled fluid-structure-thermal analysis is performed with a parameter study. The proposed method is validated to be accurate and efficient against commercial software simulation. Results have shown that the mechanical instability of the HCS plates can be induced by fluid-structure coupling and further accelerated by thermal effect. The influences of geometric parameters on thermal buckling and dynamic stability present opposite tendencies, indicating a tradeoff is required for the TPS design. The present analytical model and numerical results provide design guidance in the practical application of the novel TPS.

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Effect of crack on free vibration of a pre-stressed curved plate

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406221994869 ◽

2021 ◽

pp. 095440622199486

Author(s):

Can Gonenli ◽

Hasan Ozturk ◽

Oguzhan Das

Keyword(s):

Finite Element ◽

Free Vibration ◽

Natural Frequency ◽

Present Model ◽

Mode Shapes ◽

Load Parameter ◽

Flexible Plate ◽

Cantilever Plate ◽

Finite Element Software ◽

Aspect Ratios

In this study, the effect of crack on free vibration of a large deflected cantilever plate, which forms the case of a pre-stressed curved plate, is investigated. A distributed load is applied at the free edge of a thin cantilever plate. Then, the loading edge of the deflected plate is fixed to obtain a pre-stressed curved plate. The large deflection equation provides the non - linear deflection curve of the large deflected flexible plate. The thin curved plate is modeled by using the finite element method with a four-node quadrilateral element. Three different aspect ratios are used to examine the effect of crack. The effect of crack and its location on the natural frequency parameter is given in tables and graphs. Also, the natural frequency parameters of the present model are compared with the finite element software results to verify the reliability and validity of the present model. This study shows that the different mode shapes are occurred due to the change of load parameter, and these different mode shapes cause a change in the effect of crack.

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