Optimum geometry of tuned liquid column-gas damper for control of offshore jacket platform vibrations under seismic excitation

Mousavi, Seyed Amin; Zahrai, Seyed Mehdi; Bargi, Khosrow

doi:10.1007/s11803-012-0143-z

Cited by 29 publications

(13 citation statements)

References 15 publications

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“…Huo and Li [20] analysed the performance of a circular TLCD in suppressing the torsion-induced vibration of an offshore platform. Mousavi et al [21,22] evaluated the effectiveness of a Tuned Liquid Column Gas Damper (TLCGD) in the suppression of seismic-induced vibrations of steel jacket platforms. TLCD was also applied to floating wind turbines to reduce the vibration resulting from the wind and wave forces [23][24][25][26].…”

Section: Novel S-shaped Tlcdmentioning

confidence: 99%

A New Energy-Absorbing Device for Motion Suppression in Deep-Sea Floating Platforms

Zeng¹,

Yu²,

Zhang³

et al. 2014

Energies

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Deep-sea floating platforms are one of the most important large structures for ocean energy exploitation. A new energy-absorbing device named S-shaped Tuned Liquid Column Damper (TLCD) has been invented for the suppression of the horizontal motion and vertical in-plane rotation of a deep-sea floating platform. A conventional tuned liquid column damper has a U-shaped water tunnel to absorb the excessive energy of the main structure. The application of U-shaped dampers in deep-sea floating platforms is difficult due to the restriction of a large horizontal length. A novel S-shaped damper is proposed to retain the same amount of liquid using a shorter S-shaped tunnel. Theoretical and experimental works are conducted and prove that an S-shaped damper needs less than half the horizontal length to provide the same suppression as a U-shaped damper. A coupling calculation model is proposed and followed by the sensitivity analysis. The study demonstrates the applicability of the novel S-shaped damper for the motion suppression in deep-sea floating platforms.

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Section: Novel S-shaped Tlcdmentioning

confidence: 99%

A New Energy-Absorbing Device for Motion Suppression in Deep-Sea Floating Platforms

Zeng¹,

Yu²,

Zhang³

et al. 2014

Energies

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“…Excessive structural motions are significantly suppressed due to the gravitational restoring force and moment acting on the displaced liquid in the TLCD horizontal and vertical columns. Lee et al (2006), Roderick (2012), Mousavi et al (2012), and Dezvareh et al (2015) properly proved the TLCD capability in mitigating the responses of fixed or floating offshore platforms. Compatibility with the main structure configuration and surrounding environment enables the TLCD installation and exploitation whether to an existing or future floating breakwaters.…”

Section: Damping Device Selectionmentioning

confidence: 88%

Structural control of the floating breakwaters by implementation of tuned liquid column damper

Shahrabi

Bargi

2020

Advances in Structural Engineering

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The growing maritime activities have led offshore engineers to the application of floating breakwaters to protect coastlines from erosion and to provide a layer of support to ports in the case of strong wave actions. In these applications, minimizing the floating part responses to wave-induced excitations as one of the most critical operational characteristics would be a key factor. In this article, the structural responses of the floating breakwaters are studied through modeling and simulation. To mitigate the floating part wave-induced vibrations, an attached tuned liquid column damper is integrated into the simulation. In the first stage, the numerical model of the floating breakwater system containing the floating body and the mooring system is created. Then, by proposing an iterative coupling procedure, the joint tuned liquid column damper-floating breakwater model is developed. Several rigorous study cases are defined to evaluate the effect of tuned liquid column damper on controlling the floating body unwanted vibrations. In this application, the Airy wave theory and the Joint North Sea Wave Observation Project wave spectrum are used for wave excitations. In order to evaluate the effect of tuned liquid column damper on floating breakwaters, some design parameters like floating body motions and mooring system-mobilized tensile stresses are evaluated. The simulations are conducted in both the time domain and the frequency domain for cases with and without tuned liquid column damper. The rain flow counting method is applied to perform the mooring system fatigue analysis. The study results clearly proved that implementation of tuned liquid column damper would mitigate the floating body responses compared to the original floating breakwater system. In addition, it is indicated that the fatigue-induced failure risks in tuned liquid column damper-floating breakwater mooring system is decreased that would reduce the procurement costs and increase the operational safety of the floating breakwater system.

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“…Excessive motions of the main structure are significantly suppressed by the gravitational restoring forces and moments acting on the displaced liquid in the horizontal and vertical columns. Lee et al (2006), Roderick (2012), Mousavi et al (2012), and Dezvareh et al (2015) proved the effectiveness of the TLCD at mitigating the responses of fixed or floating offshore platforms. However, the influence of the TLCD on the fatigue behavior of mooring lines for floating structures has not been studied.…”

Section: Tuned Liquid Column Dampermentioning

confidence: 97%

Enhancement the Fatigue Life of Floating Breakwater Mooring System Using Tuned Liquid Column Damper

Shahrabi

Bargi

2019

Lat. Am. j. solids struct.

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Safety is a key design criterion for floating structures. A high rate of mooring accidents has been reported over the past decades. Preventing mooring line failure is a key design objective for floating breakwater systems. The mooring system comprises sets of mooring lines anchored to the seabed. These components are exposed to highly cyclic nonlinear load fluctuations induced by an irregular wave climate during their service life. DNVGL-OS-E301 classifies the mooring lines for floating breakwaters as long-term elements that should be evaluated according to the fatigue limit state. Fatigue of mooring lines needs to be monitored and evaluated to warrant the station keeping and integrity of overall system. Applying an additional control device to a floating breakwater mitigates the structural response and hence mobilized tension in mooring system. The focus of present study was to examine the effect of an additional control device on fatigue life of mooring lines for floating breakwaters. To evaluate the effect of a control device on the fatigue behavior of mooring lines, a floating breakwater was simulated with a tuned liquid column damper (TLCD) attached. A time-dependent approach based on S-N curves in conjunction with the Palmgren-Miner rule was employed to evaluate the mooring line fatigue. This paper presents a further parametric study focused on the effect of TLCD on fairlead point displacement, mobilized tension, damage rate, and fatigue life of mooring lines. The results showed that TLCD increased the fatigue life of mooring line and thus dramatically decreased the likelihood of the mooring system being damaged by fatigue. This would reduce the maintenance costs and increase the lifetime and operational safety of floating breakwater. In addition, the presented case study showed that failure probability of mooring lines against fatigue damage was also reduced and was acceptable for the safety factor defined in DNVGL-OS-E301. This proposed approach of applying a TLCD is a practical tool for designing the components of a floating breakwater more efficiently. Keywords floating breakwater (FB); tuned liquid column damper (TLCD); fatigue assessment; mooring system; S-N curves; structural control Enhancement the Fatigue Life of Floating Breakwater Mooring System Using Tuned Liquid Column Damper Mostafa Shahrabi et al.

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Optimum geometry of tuned liquid column-gas damper for control of offshore jacket platform vibrations under seismic excitation

Cited by 29 publications

References 15 publications

A New Energy-Absorbing Device for Motion Suppression in Deep-Sea Floating Platforms

A New Energy-Absorbing Device for Motion Suppression in Deep-Sea Floating Platforms

Structural control of the floating breakwaters by implementation of tuned liquid column damper

Enhancement the Fatigue Life of Floating Breakwater Mooring System Using Tuned Liquid Column Damper

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