Acceleration-oriented design optimization of ice-resistant jacket platforms in the Bohai Gulf

Liu, Xiang; Li, Gang; Yue, Qianjin; Oberlies, Robert

doi:10.1016/j.oceaneng.2009.09.008

Cited by 22 publications

(7 citation statements)

References 8 publications

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“…The variety of modelling approaches and dependence of the ice load on the structural properties have caused modelling and design difficulties. For instance, there is no method for choosing the proper dynamic ice case for the design and optimization of an ice-resistant jacket platform [22,23]. In addition, most IIV models do not consider the influence of fluid flow even though most structures subjected to IIVs are offshore structures.…”

Section: Motivationmentioning

confidence: 99%

Vibrations due to Flow-Driven Repeated Impacts

Jeong

Baddour

2013

Mathematical Problems in Engineering

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We consider a two-degree-of-freedom model where the focus is on analyzing the vibrations of a fixed but flexible structure that is struck repeatedly by a second object. The repetitive impacts due to the second mass are driven by a flowing fluid. Morison’s equation is used to model the effect of the fluid on the properties of the structure. The model is developed based on both linearized and quadratic fluid drag forces, both of which are analyzed analytically and simulated numerically. Conservation of linear momentum and the coefficient of restitution are used to characterize the nature of the impacts between the two masses. A resonance condition of the model is analyzed with a Fourier transform. This model is proposed to explain the nature of ice-induced vibrations, without the need for a model of the ice-failure mechanism. The predictions of the model are compared to ice-induced vibrations data that are available in the open literature and found to be in good agreement. Therefore, the use of a repetitive impact model that does not require modeling the ice-failure mechanism can be used to explain some of the observed behavior of ice-induced vibrations.

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Section: Motivationmentioning

confidence: 99%

Vibrations due to Flow-Driven Repeated Impacts

Jeong

Baddour

2013

Mathematical Problems in Engineering

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“…Since the 1980s, Chinese scholars studied the preventive measures of sea ice disasters (Ouyang et al, 2017;Lu, 1993;Wang et al, 2011;Zhang et al 2015), sea ice measurement and forecast (Luo et al, 2004;Zhao et al, 2014;Su and Wang, 2012), engineering coping strategies (Zhang et al, 2010(Zhang et al, , 2016, and mechanisms (Yue et al, 2009;Li et al, 2008;Liu et al, 2009;Huang and Li, 2001;Wang et al, 2018;Yue et al, 2007a). Most studies on existing sea ice risk assessment only involved descriptions of sea ice.…”

Section: Introductionmentioning

confidence: 99%

Risk assessment of sea ice disasters on fixed jacket platforms in Liaodong Bay

Yuan

Liu

et al. 2020

Nat. Hazards Earth Syst. Sci.

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Abstract. Sea ice disasters seriously threaten the structural safety of oil platforms in the Bohai Sea. Therefore, it is necessary to carry out a risk assessment of sea ice disasters on oil platforms in the Bohai Sea. In this study, a risk assessment of sea ice disasters on fixed jacket platforms in Liaodong Bay, in the Bohai Sea, was performed in five steps. Firstly, the formation mechanisms of sea ice disasters were analyzed and the sources and modes of sea ice risks were summarized. Secondly, according to the calculation formulas of extreme ice force, dynamic ice force, and accumulated force, several ice indices such as thickness, motion, strength, period, and concentration were proposed as the hazard indices, and corresponding values were then assigned to the proposed indices based on ice conditions in the Bohai Sea. Thirdly, based on four structural failure modes – structural overturning by extreme ice force (Mode 1), structural fracture failure caused by dynamic ice force (Mode 2), the damage of facilities caused by dynamic ice force (Mode 3), and structural function failure caused by accumulated ice (Mode 4) – the structural vulnerability index, overturning index, dynamic index, ice-induced vibration index, and function index were proposed, and corresponding values were assigned to the structural vulnerability index of fixed jacket platforms in Liaodong Bay. Fourthly, the weight of each risk index was determined according to previously recorded sea ice disasters and accidents, and the sea ice risk was then calculated with the weighted synthetic index method. Finally, with the above index system and risk assessment methods, the risk assessment of sea ice disasters on 10 jacket platforms in three sea areas in Liaodong Bay was carried out. The analysis results showed that efficient sea ice prevention strategies could largely mitigate the sea ice-induced vibration-related risks of jacket platforms in Liaodong Bay. If steady-state vibration occurs (usually in front of the vertical legged structure) or the structural fundamental frequency is high, the structural vulnerability is significantly increased and the calculated risk levels are high. The sea ice risk assessment method can be applied in the design, operation, and management of other engineering structures in sea ice areas.

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“…Wang et al [22] discussed the way of adding ice-breaking cones at the water level, which will decrease the amplitude of ice loads and change the ice breaking frequency to reduce the vibrations. Liu et al [23] adopted the finite element method analysis to show that the ice-induced vibration can be significantly reduced for JZ20-2MUQ jacket platform with the isolation cone system. In order to achieve an economical and rational design with the consideration of structural and non-structural performances, Karr et al [24] used an acceleration-oriented design optimization of ice-resistant jacket platforms in the Bohai Gulf.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Performance Analyses and Optimal Gain-Scheduling Control of Offshore Wind Turbine Under Ice Creep Loads

Song

Liu

et al. 2019

IEEE Access

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At high latitudes, offshore wind turbines often face unfavorable loads by severe ice-induced vibrations during winter season, which may endanger facilities available on the platforms and degrade operating performance of wind turbine. Hence, it is vital to analyze the influences caused by ice loads. In this paper, based on a real-time simulation model, quantifiable analyses of performance losses due to ice creep loads are firstly studied deeply. Under ice creep loads, reliable pitch control is necessary to ensure safety and high-level power-tracking capability of modern offshore wind turbine. However, uncertain influences of ice creep loads are coupled with wind turbine operation and make it a challenge for wind turbine pitch control using traditional Proportional-Integral (PI) controller from the view of industry. As a result, improved pitch control using optimal gain-scheduling strategy is proposed to alleviate impacts of ice loads where the support vector regression algorithm is adopted to represent the strong nonlinear relationship among PI parameters under different operation conditions. For each operation point, PI parameters are optimally tuned by the particle swarm optimization algorithm. Finally, the presented nonlinear optimal gain-scheduling PI (OGS-PI) controller is applied on regulating generation power and reducing tower top displacement caused by ice creep loads based on software of Fatigue, Aerodynamics, Structures, and Turbulence, a high-fidelity wind turbine simulator. Simulation results show that unfavorable influence of ice creep loads to wind turbine operation can be significantly alleviated by the OGS-PI controller, which performs much better than the traditional PI controller. INDEX TERMS Offshore wind turbine, ice loads, gain-scheduling control, optimal control, real-time.

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Acceleration-oriented design optimization of ice-resistant jacket platforms in the Bohai Gulf

Cited by 22 publications

References 8 publications

Vibrations due to Flow-Driven Repeated Impacts

Vibrations due to Flow-Driven Repeated Impacts

Risk assessment of sea ice disasters on fixed jacket platforms in Liaodong Bay

Real-Time Performance Analyses and Optimal Gain-Scheduling Control of Offshore Wind Turbine Under Ice Creep Loads

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