Time-domain numerical and segmented ship model experimental analyses of hydroelastic responses of a large container ship in oblique regular waves

Chen, Zhanyang; Jiao, Jing; Li, Hui

doi:10.1016/j.apor.2017.07.005

Cited by 25 publications

(5 citation statements)

References 11 publications

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“…Parameters update computation is executed for each course change. When the parameters have been updated by this manoeuvring, the ship will thereafter be manoeuvred according to the new parameters (Chen et al, 2017). The initial set values for the EKF-DRNN control parameters are entered at the time of installation based on the hull design dimensions.…”

Section: Ship Characteristics and Sea State Estimationmentioning

confidence: 99%

EKF-DRNN autopilot for VLCC heading hybrid control

Chen

2021

Transactions of the Institute of Measurement and Control

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An online Extended Kalman Filter (EKF)-Dynamic Recurrent Neural Network (DRNN) autopilot implementation strategy for Very Large Crude Carrier (VLCC) heading hybrid control with uncertain dynamics is designed in this paper. The autopilot scheme is based on a DRNN control model, which learns VLCC dynamic characteristics, while the VLCC heading control is estimated by the EKF to minimize squared course error. The online EKF-DRNN autopilot provides optimal control on the basis of fuel-saving evaluation criteria using the heading deviation and rudder angle. Therefore, the autopilot output is guaranteed to converge to the desired VLCC trajectory asymptotically. The proposed strategy is evaluated by applying it to VLCC Yuan Kun Yang from COSCO Shipping, and works excellently under different loads, speed and weather conditions. The VLCC heading hybrid controller is also assessed by ‘Z’ manoeuvring and turning test, and the superiority of the online EKF-DRNN autopilot is demonstrated. The remote online monitoring of Yuan Kun Yang’s main navigation data shows that it improved fuel-saving properties despite worsening weather conditions causing increased yawing.

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Section: Ship Characteristics and Sea State Estimationmentioning

confidence: 99%

EKF-DRNN autopilot for VLCC heading hybrid control

Chen

2021

Transactions of the Institute of Measurement and Control

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“…For ships in irregular waves, the wave memory effects which result from the persistence of radiated waves generated by the ship's motion and its scattering of incident irregular waves play an import role in the determination of radiation wave force. The radiation wave force in irregular waves can be expressed as [25]:…”

Section: Radiation Wave Forcementioning

confidence: 99%

Investigation on Ship Hydroelastic Vibrational Responses in Waves

Xia

Jia

et al. 2018

Applied Sciences

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The hydroelastic vibrational responses of a large ship sailing in regular and irregular head waves are investigated numerically and experimentally. A 3D time-domain nonlinear hydroelastic mathematical model is established in which the hydrostatic restoring forces and incident wave forces are calculated on the instantaneous wetted hull surface to consider nonlinear effects of the rigid motion and elastic deformation of the hull in harsh waves. Radiation and diffraction wave forces are computed on the mean wetted surface based on the 3D frequency-domain potential flow theory. The slamming loads are calculated by momentum theory and integrated into the hydrodynamic forces. The 1D Timoshenko beam theory is adopted to model the vibrational structural response and is fully coupled with the presented hydrodynamic theory in time-domain to generate the hydroelastic equation of motion. Moreover, self-propelled segmented model tests were conducted in a laboratory wave tank to experimentally investigate the hydroelastic responses of a target ship in regular and irregular head seas. The numerical and experimental results are systemically compared and analyzed, and the established hydroelastic analysis model turns out to be reliable and effective in the prediction of ship hydroelastic responses in waves.Early research efforts mainly focused on 2D theories in which 2D strip theories, linear or nonlinear, are adopted to analyze the hydrodynamics, while the elastic responses of the ship are represented by the modal superposition method [2][3][4]. With the advent and popularization of high-performance computers, 3D hydroelastic analysis gradually captured the attention of the marine community, especially for the cases where the assumptions of the strip method are not appropriately satisfied [5,6]. The fluid flow is modeled by the 3D potential flow theory, and the ship structure is considered using a 1D or 3D finite element (FE) model [7][8][9]. Recently, Computational Fluid Dynamics (CFD) simulation of fluid flow has been incorporated into the methodology of hydroelasticity [10,11], but the immense amount of time required at present hinders the development of this process, and makes it impractical for use in practical engineering applications.Together with the development of a theoretical approach is the experimental investigation. Small scale ship model tests in towing tanks have been widely conducted to study hydroelastic responses, such as vertical motions and bending moments, with the experimental conditions ranging from moderate seas to high seas [12][13][14]. Besides those small scale model tests, large scale model tests and even the full-scale ship tests have been conducted to further enhance the understanding of fluid-structure interaction mechanisms [15][16][17][18]. A benchmark study on the performance of seventeen hydroelastic analysis codes applied to a target containership was carried out [19]. The hydroelastic model experiment of the target containership was conducted to further test each seakeeping code. Comprehensi...

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“…To date, majority of the literature work are focusing on the investigation of ship hydroelastic responses in regular waves [20][21][22]. However, the realistic irregular waves are much more complex compared with the regular waves and they are associated with strongly nonlinearity and randomicity.…”

Section: Introductionmentioning

confidence: 99%

Predictions of Ship Extreme Hydroelastic Load Responses in Harsh Irregular Waves and Hull Girder Ultimate Strength Assessment

Jia

Jiang

Zhang³

et al. 2019

Applied Sciences

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In this paper, the hydroelastic motion and load responses of a large flexible ship sailing in irregular seaways are predicted and the hull girder ultimate strength is subsequently evaluated. A three-dimensional time-domain nonlinear hydroelasticity theory is developed where the included nonlinearities are those arising from incident wave force, hydrostatic restoring force and slamming loads. The hull girder structure is simplified as a slender Timoshenko beam and fully coupled with the hydrodynamic model in a time domain. Segmented model towing-tank tests are then conducted to validate the proposed hydroelasticity theory. In addition, short-term and long-term predictions of ship responses in irregular seaways are conducted with the help of the developed hydroelastic code in order to determine the extreme design loads. Finally, a simplified strength-check equation is proposed, which will provide significant reference and convenience for ship design and evaluation. The hull girder ultimate strength is assessed by both the improved Rule approach and direct calculation.

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Time-domain numerical and segmented ship model experimental analyses of hydroelastic responses of a large container ship in oblique regular waves

Cited by 25 publications

References 11 publications

EKF-DRNN autopilot for VLCC heading hybrid control

EKF-DRNN autopilot for VLCC heading hybrid control

Investigation on Ship Hydroelastic Vibrational Responses in Waves

Predictions of Ship Extreme Hydroelastic Load Responses in Harsh Irregular Waves and Hull Girder Ultimate Strength Assessment

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