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Ice-Class Propeller Strength and Integrity Evaluation Using Unified Polar ClassURI3 Rules

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Journal of Ocean University of China 2021年第4期20卷 823-836页

作者： LI Qi LIU Pengfei Australian Maritime College University of TasmaniaLauncestonTasmania 7250Australia marine Offshore and Subsea TechnologySchool of EngineeringNewcastle UniversityNewcastle upon TyneNE17RUUK

A systematic method was developed for ice-class propeller modeling,performance estimation,strength and integrity evaluation and *** estimate the impact of sea ice on the propeller structure,URI3 rules,established by the International Association of Classification Societies in 2007,were applied for ice loading *** R-class propeller(a type of ice-class propeller)was utilized for subsequent *** propeller modeling was simplified based on a conventional method,which expedited the model building *** propeller performance was simulated using the computational fluid dynamics(CFD)*** simulation results were validated by comparison with experimental ***,the hydrodynamic pressure was transferred into a finite element analysis(FEA)module for strength assessment of ice-class *** to URI3 rules,the ice loading was estimated based on different polar classes and working ***,the FEA method was utilized to evaluate the propeller *** validation showed that the simulation results accorded with recent research ***,an improved optimization method was developed to save the propeller constituent *** optimized propeller example had a minimum safety factor of 1.55,satisfying the safety factor requirement of≥1.5,and reduced the design volume to 88.2%of the original.

关键词： polar class propeller URI3 rules propeller blade strength and integrity design and optimization ice-class propeller hydrodynamics-strength coupled

Coupling of RANS and BEM Solvers for Simulation of Propeller Behind the Hull in Full Appended Model

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China Ocean Engineering 2024年第3期38卷 424-438页

作者： Saeed NAJAFI Mehdi POURMOSTAFA LIU Peng-fei Iranian National Institute for Oceanography and Atmospheric Science(INIOAS) Tehran 14155-4781Iran Department of Maritime Engineering Amir Kabir University of TechnologyTehran 15875-4413Iran marine Offshore and Subsea TechnologySchool of EngineeringNewcastle UniversityNewcastle upon TyneNE17RUUK

To design a propeller for ship power plant,the interaction between ship hull and propeller must be taken into *** main concern is to apply the wake effect of ship stern on the propeller *** this paper,a coupled BEM(Boundary Element Method)/RANS(Renolds-Averaged Navier−Stokes)solver is used to simulate propeller behind the hull in the self-propulsion *** motivation of this work is to develop a practical tool to design marine propulsion system without suffering long computational *** unsteady boundary element method which is also known as panel method is chosen to estimate the propeller *** wakes are treated using a time marching wake alignment ***,a RANS code coupled with VoF equation is developed to consider the ship motions and wake field effects in the problem.A coupling algorithm is developed to interchange ship wake field to the potential flow solver and propeller thrust to the RANS *** on the difference between hull resistance and the propeller thrust,a PI controller is developed to compute the propeller RPM in every time *** of the solver is carried out using the towing tank test report of a 50 m oceanography research *** factor and trust deduction coefficient are estimated ***,the wake rollup pattern of the propeller in open water is compared with the propeller in real wake field.

关键词： RANS BEM coupled method ship propeller self-propulsion wake sheet pattern

Experimental Investigation of Wave Slamming on An Open Structure Supported Elastically

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China Ocean Engineering 2016年第6期30卷 967-978页

作者：任冰刘明李雪临王永学 State Key Laboratory of Coastal and offshore Engineering Dalian University of Technology Department of marine Strategy Research & Planning National Ocean Technology Center State Oceanic Administration

The superstructures of marine structures supported by the elastic legs and located in the splash zone will subject to violent wave slamming and vibrate consequently during storms. A series of model tests are carried out to investigate the wave impacting on the open structures supported elastically. Three kinds of models with different natural frequencies are designed. The characteristics of the wave pressures on the three models are compared. The durations of the uplift forces and the corresponding accelerations of the structure during wave impact are analyzed simultaneously. The distributions of the peak impact pressures on the subfaces of the plates with different supporting stiffness are given. The relationship between the uplift force on the three models and the relative clearance are obtained. The spectral properties of the slamming loads on the three different structures are compared, The experimental results indicate that the behaviors of the impact pressures, the uplift forces and accelerations of the plates with small natural frequencies are obviously different from those of the plates with larger natural frequencies within the range of the experimental parameters.

关键词： supported elastically wave impact acceleration hydro-elasticity

A useful guide of effective mesh-size decision in predicting the ultimate strength of flat-and curved plates in compression

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Journal of Ocean Engineering and Science 2023年第4期8卷 401-417页

作者： Do Kyun Kim Imjun Ban Bee Yee Poh Sung-Chul Shin Department of Naval Architecture and Ocean Engineering College of EngineeringSeoul National UniversitySeoulSouth Korea Research Institute of marine Systems Engineering Seoul National UniversitySeoulKorea group of marine Offshore and Subsea Technology(MOST)School of EngineeringNewcastle UniversityNewcastle upon TyneUK Department of Naval Architecture and Ocean Engineering Pusan National UniversityBusanSouth Korea Ocean and Ship technology Research group Department of Civil and Environmental EngineeringPETRONAS University of TechnologySeri IskandarPerakMalaysia

The present study aims to determine the appropriate size of mesh or the number of the element(NoE)for flat-and curved plates,which is suggested to assess its safety subjected to axial compression based on the ultimate limit state(ULS)design and analysis *** unstiffened panel(=plate)and stiff-ened panel,considered primary members of ships and ship-shaped offshore structures,are subjected to repeated axial compression and tension caused by continued vertical bending moments applied to the hull *** are attached with stiffeners by welding,and 6,8 or 10 elements are generally rec-ommended to allocate in flat-plate’s breadth direction in between stiffeners for finite-element(FE)mod-elling,which enables the presentation of the shape of initial deflection applied to the *** the case of the load-shorting curve for curved plate,it is reported that the nonlinear behaviour characteristics,i.e.,snap-through,snap-back,secondary buckling and others,appear in typical flank *** take this into account,we investigated the preferred number of elements(6,8 or 10)generally applied to the flat plate whether it is an appropriate or more fine-sized element(or mesh)that should be considered.A useful guide is documented based on obtained outcomes which may help structural engineers select optimised mesh-size to predict ultimate strength and understand its characteristic of the flat and curved plates.

关键词： Ultimate strength Unstiffened panel Longitudinal compression Mesh convergence Finite-element method

Time-varying reliability indexes for multi-AUV cooperative system

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Journal of Systems Engineering and Electronics 2017年第2期28卷 401-406页

作者： Qingwei Liang Tianyuan Sun Dongdong Wang College of marine Science and technology Northwestern Polytechnical University Xi’an 710072 China The 32nd Research Institute of China Electronic technology group Corporation Shanghai 200233 China

With the development of multi-autonomous underwater vehicle (AUV) cooperative systems, the evaluation of their reliability is becoming more and more important. Since AUVs are always in motion, the reliability of the system is not stationary, but it varies with time. This paper studies the time-varying reliability evaluation indexes for multi-AUV cooperative systems. Aimed at elucidating the characteristics of the system, by considering the motion of the AUVs, two time dependent reliability evaluation indexes, natural connectivity and all-terminal reliability of the basic reliability indexes, are determined with the graph theory. Then the time-varying reliability of multi-AUV cooperative systems is evaluated combining with an actual example. This paper provides a method to evaluate the time-varying reliability of multi-AUV cooperative systems. © 2017 Beijing Institute of Aerospace Information.

关键词： Graph theory offshore pipelines Reliability Reliability theory

Reliability indexes for multi-AUV cooperative systems

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Journal of Systems Engineering and Electronics 2017年第1期28卷 179-186页

作者： Qingwei Liang Tianyuan Sun Dongdong Wang College of marine Science and technology Northwestern Polytechnical UniversityXi’an 710072China The 32th Research Institute of China Electronic technology group Corporation Shanghai 200233China

With the development of multi-autonomous underwater vehicle (AUV) cooperative systems, the evaluation of their reliability is becoming more and more important. Aimed at the characteristics of the system, three reliability indexes-standard entropy of rank distribution, all-terminal reliability and standard natural connectivity are determined in this paper. Topology structure and underwater acoustic communication are considered. The calculation methods of the three reliability indexes are proposed, and the characteristics of these indexes are analyzed. The reliability indexes of two multi-AUV cooperative systems are obtained as examples. Results show that these three indexes reflect different aspects of reliability for multi-AUV cooperative systems. This paper provides some methods to evaluate the reliability of multi-AUV cooperative systems, which is of practical value. © 1990-2011 Beijing Institute of Aerospace Information.

关键词： Cooperative communication offshore pipelines Reliability Underwater acoustics

Simulation of Horizontal-Two-Dimension Focused Waves Using A Two-Layer Boussinesq-Type Model

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China Ocean Engineering 2023年第5期37卷 725-737页

作者： ZOU Wen-feng WANG Ping LIU Zhong-bo FANG Ke-zhao SUN Jia-wen ZHANG Ning-chuan Key Laboratory of coastal and offshore engineering Dalian University of TechnologyDalian 116024China State Environmental Protection Key Laboratory of marine Ecosystem Restoration National Marine Environmental Monitoring CenterDalian 116023China Dalian Maritime University College of Transportation EngineeringDalian 116024China

Accurate simulation of the horizontal-two-dimension(H2D)focused wave group in deep water requires high accuracy of a numerical *** two-layer Boussinesq-type model(Liu and Fang,2016;Liu et al.,2018)with the highest spatial derivative of 2 has high accuracy in both linear and nonlinear *** on the further development of the velocity equations(Liu et al.,2023),the H2D numerical model for water waves is established with the prediction-correction-iteration model in the finite difference method,and a composite fourth-order Adams-Bashforth-Moulton scheme is used for time *** wave generation method proposed by Hsiao et al.(2005)is applied and calibrated in this H2D *** numerical calculations lead to the following three main conclusions:First,compared with the analytical solution of Stokes linear waves,the calculated velocity profiles show higher accuracy by using the improved velocity ***,the simulations of the focused multidirectional wave group are carried out,and good agreements are found,demonstrating that the present H2D numerical model shows high accuracy in simulating focused multidirectional wave groups,and the effectiveness of the improved velocity formulas is also ***,the velocity profiles throughout the computational domain at the time of maximum wave crest are ***,the FFT method is used to obtain the amplitude with different frequencies for several locations,and the changes of the wavelet energy spectrum at different locations are presented for several cases.

关键词： focused wave horizontal-two-dimension model finite difference method nonlinear property

An Installation System of Deepwater Risers by An S-Lay Vessel

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China Ocean Engineering 2011年第1期25卷 139-148页

作者：段梦兰王懿 Segen ESTEFEN 何宁李丽娜陈邦敏 School of Naval Architecture and marine Engineering Dalian University of Technology offshore Oil/Gas Research Center China University of Petroleum COPPE Federal University of Rio de Janeiro Design Division CNOOC Engineering

Along with the consumption increase of the petroleum products, more countries have transferred their attentions to the offshore fields, especially the deepwater oil and gas reserves. For deepwater exploitation, the risers must be installed to act as the conduits connecting surface platforms to subsea facilities. In this paper, the typical risers sorted by different classes are introduced, and the correspondent installation methods are presented. By investigating the recent projects performed in the deepwater hot spots, and combining the challenges of HYSY20 l for riser installation, a lifting device developed for assisting riser installation is proposed and detailed to satisfy the installation of deepwater risers in the LW3-1 Gas Field of 1500 m in the South China Sea. Tests on both the functions and performances of such a new system exhibit the satisfaction of meeting all challenging requirements of HYSY201 for application to riser installation in waters up to a depth of 3000 m in the South China Sea.

关键词： deepwater riser riser installation lifting device LW3-1 Gas Field South China Sea

Application of a collaborative modelling and strategic fuzzy decision support system for selecting appropriate resilience strategies for seaport operations

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Journal of Traffic and Transportation Engineering(English Edition) 2014年第3期1卷 159-179页

作者： Andrew John Zaili Yang Ramin Riahi Jin Wang Department of marine and offshore Engineering School of Engineering Technology and Maritime OperationsLiverpool John Moores UniversityLiverpoolMersey sideUK

The selection of an appropriate resilience investment strategy to optimize the operational efficiency of a seaport is a challenging task given that many criteria need to be considered and modelled under an uncertain environment. The design of such a complex decision system consists of many subjective and imprecise parameters contained in different quantitative and qualitative forms. This paper proposes a fuzzy multi-attribute decision making methodology for the selection of an appropriate resilience investment strategy in a succinct and straightforward manner. The decision support model allows for a collaborative modelling of the system by multiple analysts in a group decision making process. Fuzzy analytical hierarchy process （FAHP） was utilized to analyse the complex structure of the system to obtain the weights of all the criteria while fuzzy technique for order of preference by similarity to ideal solution （TOPSIS） was employed to facilitate the ranking process of the resilience strategies. Given that it is often financially difficult to invest in all the resilience strategies, it is envisaged that the proposed approach could provide decision makers with a flexible and transparent tool for selecting appropriate resilience strategies aimed at increasing the resilience of seaport operations.

关键词： seaport resilience FAHP TOPSIS decision making