Experimental evaluation of a mooring system simplification methodology for reducing mooring lines in a VLFS model testing at a moderate water depth

Liang, Mingxiao; Xu, Shengwen; Wang, Xuefeng; Ding, Aibing

doi:10.1016/j.oceaneng.2020.107912

Cited by 7 publications

(4 citation statements)

References 20 publications

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“…This model is intended to be deployed in the Southern China Sea and has been tested experimentally in the State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University (SJTU) model test basin with a scale ratio of 1:100. The model has been under scrutinized from different perspectives and purposes, such as mooring system (Mingxiao Liang, 2021), response prediction (YutuYe, 2022), and hydrodynamic studies (Yiting Wang, 2022). The model consists of one extended upper deck and ten columns with five pontoons, where three mooring systems have been tested, even though for the current simulation setting, only the taut mooring has been employed (Figure 4).…”

Section: 1mentioning

confidence: 99%

Real-Time Sea State Estimation Using Deep Transfer Learning; an Integrated Framework

Majidiyan,

Enshaei,

Howe

2024

Preprint

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This study addresses the crucial need for wave parameter identification in floating units at sea, where waves serve as a primary environmental force. Despite decades of research, online wave estimation using ship-borne sensors, known as the wave buoy analogy (WBA), has not provided a definitive solution for deterministic sea state estimation. Our study proposes an integrated AI system that minimizes the time lag between the excitation wave and wave estimation based on the current state. Our innovative approach involves a threshold self-exciting mechanism, dynamically switching between different predictors based on statistical characteristics within a fixed observation window of ship responses. This mechanism adjusts the buffer window for wave estimation. Time-series responses from a moored semi-submersible simulation undergo preprocessing to extract detailed spectral and temporal features. This data is then transformed into scalograms and fed into a deep-learning network. A novel aspect of our work involves exploring transfer learning and leveraging off-the-shelf networks to accelerate the training process. The present setting not only effectively reduces time lag but also showcases the potential of transfer learning for generalizing sea state estimation models. The promising outcomes of this research, in turn, pave the way for advanced seakeeping capabilities and safer marine operations.

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Section: 1mentioning

confidence: 99%

Real-Time Sea State Estimation Using Deep Transfer Learning; an Integrated Framework

Majidiyan,

Enshaei,

Howe

2024

Preprint

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“…Gomes et al [24] conducted an experimental study on the buoy-swinging wave energy converter of the fve-device array in the wave pool with diferent confgurations, focusing on the analysis of the device's motion and mooring tension. Liang et al [25] evaluated the feasibility of the simplifed mooring system by model experiment on a very large foating structure (VLFS) mooring system which is composed of 20 mooring chains. Gao et al [26] conducted a series of tests in a tank with a model scale of 1 : 70 to study the dynamic response of mooring line based on catenary structure when wave and heave motions were applied.…”

Section: Introductionmentioning

confidence: 99%

Modeling and Numerical Simulation of Semitensioned Mooring Line under Taut-Slack State

Shi

Zhang

Liu

et al. 2023

Shock and Vibration

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In this paper, considering the mooring system can be taut-slack in the motion, the dynamic equations of the mooring system are derived by using the theory of large deformation. The nonlinear dynamic response of semitensioned mooring line is numerically simulated. Assuming the platform motion is known, the effect of platform on mooring line is simplified as an end-point excitation. Directly using the finite difference method for numerically solving partial differential equations of mooring line, the dynamic responses can be obtained. Then, the causes about the nonlinear state are analyzed, and the location where the taut-slack phenomenon occurs can be located by calculating the tension of mooring. The results show that the mooring line is more likely to be taut-slack under tangential excitation with the tension change, while the mooring remains taut under normal excitation. The taut-slack state of the mooring line is concentrated near the anchor point. Through the amplitude-frequency curve and bifurcation point set, it is found that the taut-slack region is accompanied by multiperiod motion. And the taut-slack phenomenon will lead to the unstable motion.

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“…For the MFS, the mooring system is of great importance [24,25]. Due to the large number of modules, relative movement inevitably occurs between adjacent modules under waves.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Analysis of a Novel Modular Floating Structure System Integrated with Floating Artificial Reefs and Wave Energy Converters

Ren

et al. 2022

JMSE

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A novel modular floating structure (MFS) system moored by tension legs was proposed, which is composed of hexagonal floating modules, floating artificial reefs and wave energy converters (WECs). The integration of floating artificial reefs and WECs into the MFS can improve the marine environment and produce considerable electricity. The effects of both wave characteristics and the module quantity on the hydrodynamic responses of the MFS system were studied in depth, based on a time-domain numerical model. Both the modules’ hydrodynamic interaction effect and the connectors’ mechanical coupling effect were considered. The results indicate that floating artificial reefs combined with WECs can effectively reduce wave loads and convert wave energy into electricity for the MFS system. More modules involved in the MFS system could significantly reduce motion response and produced more wave energy output, which indicates that the MFS system is suitable for large-scale expansion. The effect of different power take-off (PTO) damping coefficients on the WECs’ performance was further investigated, and the optimal damping coefficient was recommended for the MFS system. Finally, the main extreme responses of the MFS system were further investigated, and its safety was checked thoroughly. One survival strategy was proposed, which could efficiently reduce extreme connector loads by more than 50%.

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Experimental evaluation of a mooring system simplification methodology for reducing mooring lines in a VLFS model testing at a moderate water depth

Cited by 7 publications

References 20 publications

Real-Time Sea State Estimation Using Deep Transfer Learning; an Integrated Framework

Real-Time Sea State Estimation Using Deep Transfer Learning; an Integrated Framework

Modeling and Numerical Simulation of Semitensioned Mooring Line under Taut-Slack State

Hydrodynamic Analysis of a Novel Modular Floating Structure System Integrated with Floating Artificial Reefs and Wave Energy Converters

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