Nonlinear impact response analysis of LNG FPSO cargo tank structures under sloshing loads

Lee, Sang Eui; Kim, Bong Ju; Seo, Jung Kwan; Ha, Yeon Chul; Matsumoto, Toshiyuki; Byeon, Su Hwan; Paik, Jeom Kee

doi:10.1080/17445302.2015.1022437

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…Kim et al (2007) compared two numerical methods, the finite-difference method and the smoothed-particle-hydrodynamics (SPH) method, to investigate the strongly nonlinear sloshing flows, which verified that the nonlinearity of the sloshing-induced forces and moments plays a critical role in the coupling effect. Lee et al (2015) performed nonlinear response in FLNG cargo tank structures under sloshing loads with ANSYS/LS-DYNA nonlinear finite element software. Paik et al (2015) determined the sloshing loads during the structural design of LNG FPSO with a new probabilistic approach.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of sloshing effect on the hydrodynamic responses of an FLNG system during side-by-side operation

Jiang

2017

Ships and Offshore Structures

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Section: Introductionmentioning

confidence: 99%

Experimental investigation of sloshing effect on the hydrodynamic responses of an FLNG system during side-by-side operation

Jiang

2017

Ships and Offshore Structures

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“…In a LNG cargo tank, sloshing is the only unpredictive load that results in its structural degradation. Sloshing studies conducted in accordance with the American Bureau of Shipping and DVN.GL guidelines suggest that the maximum and mean duration of the sloshing impact were 200 ms and 11.7-27.4 ms, respectively [29,52]. It is also suggested in reference [52] that the sloshing impacts are separated by zero pressure intervals in the order of a few seconds, and the interval between the sloshing impacts are not consistent.…”

Section: Correlation Between the Coupon Specimen And Real Structures mentioning

confidence: 99%

“…The number of discrete voltage values in a waveform depends on its window length and the sampling frequency. The damages in LNG cargo containment are likely to occur during rise-time of a typical sloshing impact (i.e., the time taken for the impact to reach the maximum value) [29]. Therefore, to capture the entire waveform generated from damage, its window length should be set equal to the rise-time of a sloshing impact that has the potential to introduce damages.…”

Section: Introductionmentioning

confidence: 99%

Validation of Acoustic Emission Waveform Entropy as a Damage Identification Feature

2019

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The increase in the market for supersized LNG (liquefied natural gas) vessels, with double wall cargo tanks, has led to concerns regarding their safe operation. If both the primary and secondary wall of the cargo tank fail simultaneously, the hull of the vessel can be exposed to the LNG. This has the potential to cause brittle failure of the hull structure. This study presents a new acoustic emission (AE) technique approach that can be implemented for monitoring the structural condition of the cargo containment. The new technique approach is based on a feature of the AE waveform, calculated using quadratic Renyi’s entropy. The presented technique is capable of providing information regarding critical damage so that appropriate maintenance can be carried out to avoid failure. The new AE technique is based on an AE feature that is independent of acquisition settings (e.g., threshold and timing), unlike many traditional AE features. The effectiveness of the proposed feature was evaluated by comparison with traditional AE features under ideal conditions for a range of varying acquisition settings. Unlike the traditional feature, the new feature demonstrated no variance with variation of the acquisition settings and was effective in capturing the collective information in the waveform. The proposed AE feature was validated through tensile and fatigue testing on standard specimens of austenitic stainless steel (material of the primary wall). The results suggest that the proposed AE feature is sensitive in identifying the critical damages irrespective of some data acquisition settings.

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“…Transient FE analysis is used to understand dynamic characteristics using the pressure-time history obtained from computational fluid dynamics (CFD) or sloshing model tests. FSI analysis is used to model the sloshing effect by considering both fluid flow and structural deformation (Lee et al 2004(Lee et al , 2013(Lee et al , 2015. ABS guidelines (2009) state that dynamic analysis should be preferentially conducted; FSI analysis is required if systems do not pass dynamic analysis.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear structural behaviour of membrane-type LNG carrier cargo containment systems under impact pressure loads at −163 °C

Sohn

Bae

et al. 2016

Ships and Offshore Structures

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This paper is a sequel to the paper dealing with quasi-static responses previously studied by the authors. The structural failure of membrane-type liquefied natural gas carrier (LNGC) cargo tank is an important issue in the construction of ultra-large an LNG carrier. However, quasi-static analysis to investigate the structural failure is difficult and tends to give conservative results. To compensate the weak points of the quasi-static analysis, a procedure for the dynamic analysis was developed to assess the structural failure using nonlinear finite element method. A nonlinear finite element method is employed to model metal membrane, insulation and surface contacts. Various element formulations are tested at different points along a corrugated surface to optimise the accuracy of the model with respect to computation time. Material properties used in the model are calibrated based on experimentally measured values at cryogenic conditions (-163°C). The model is used to predict the structural failure under different impact pressure loads and loading patterns. It is concluded that the structural damage is less likely to occur under 30 bar.

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Nonlinear impact response analysis of LNG FPSO cargo tank structures under sloshing loads

Cited by 5 publications

References 15 publications

Experimental investigation of sloshing effect on the hydrodynamic responses of an FLNG system during side-by-side operation

Experimental investigation of sloshing effect on the hydrodynamic responses of an FLNG system during side-by-side operation

Validation of Acoustic Emission Waveform Entropy as a Damage Identification Feature

Nonlinear structural behaviour of membrane-type LNG carrier cargo containment systems under impact pressure loads at −163 °C

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