A Review on the Key Technologies of Dynamic Response 

Prediction of Floating Offshore Wind Turbines

 

HU Zhiqiang^1,2

（1. School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK；

2. Harbin Engineering University,Harbin150001, China）

 

Abstract: This paper summarizes the main characteristics and the technical difficulties of floating offshore wind turbines (FOWT), as well as the analysis content and the key technologies for prediction of the dynamic responses. It describes in detail the aero-hydro-structural-servo dynamic modelling, and the related rigid-flexible multi-body dynamics analysis technologies and computational software established on that basis. The focus is put on the basin experimental technologies, such as scaling-effect, steady wind field generation in open space, blade model design and manufacturing technology, and the floating wind turbine system's inertia adjustment technology. In addition, discussions are carried out on other key technologies, including Computational Fluid Dynamics (CFD) applications, full-scale measurement, and the achievements and bottlenecks of FOWT dynamic response analysis technology, which provides reference for the future endeavours on this subject.

Key words:floating offshore wind turbine; dynamic performance; rigid-flexible multi-body system; analytical calculation; model experiment

 

 

 

Parametric Bow Design of Very Large Container Ship with Twin Skeg

 

LIANG Jiajian, LIU Yang, SU Jia, CHEN Tianyu

（Shanghai Branch of China Ship Science Research Center, Shanghai 200011, China)

 

Abstract: Ascontainer ships have the features of larger loading capacities, higher gravity center and more flexible maneuverability, there is a trend of twin skeg design. The block coefficients of large container ship are small and the wave resistance plays the major role in the total resistance. Therefore, a parametric model of the ship bow is established according to the hull characteristics of large container ships, and the wave resistances of the ship under different speeds are numerically simulated. The result shows that the wave resistance of the optimized bow for the twin skeg lines has decreased significantly compared with that of the original design and both the wave forms along the ship side and the stern wave are well improved. This means that optimized design can be applied to the hull line design of large container ships with twin skeg.

Key words:twin skeg; parametric model; wave resistance; hull lines optimization

 

 

 

Analysis of Global Loads Characteristics and

Strength of a Trimaran

 

WANG Xianzheng, LIU Jianhua

（Marine Design & Research Institute of China, Shanghai 200011, China）

 

Abstract:The global loads of Trimaran are complicated, so it is important to decide the design load and make strength check to ensure hull safety. A trimaran is taken as the project to carry out the global loads design on the basis of the rule calculations, software prediction of wave load and model tests. The relationship between transversal loads and longitudinal loads are summarized, and the global finite element method is used for structural strength check to analyze the high stress regions of the trimaran structures. This provides reference for the design of subsequent ships.

Key words:trimaran; global load; transverse loads; strength analysis

 

 

 

General Design of Small Buoy Tender Vessel Suitable for

Navigation Mark Maintenance

 

MAO Jianhui¹, SHAO Wuhao¹, HAN Yi²

（1. Marine Design & Research Institute of China, Shanghai 200011, China;

2. The Navigation Guarantee Centre of North China Sea,

Qingdao Aton Division of Ministry of Transport, Qingdao 266011, China）

 

Abstract:Through the analysis on the operation demands of small buoy tender vessel, this paper introduces the general design of the ship, the configuration characteristics of buoy clamping device, small crane and catapult device. When the potential of the vessel is fully developed, the vessel could have multi-functions to meet the daily inspection and maintenance demands such as navigation mark inspection, clamping and casting operations.

Key words:navigation mark maintenance; clamping device; small crane; catapult

 

 

 

A Research on Matching of Double-Layer Vibration Isolating System and Hull Structure Impedance

 

WU Peng¹, DONG Jiahuan², SUN Kainian³

（1. The Fourth Military Representative Office, Shanghai 200090, China;

2. Shanghai Marine Diesel Engine Research Institute, Shanghai 200090, China;

3. Jiangnan Shipyard (Group) Co., Ltd., Shanghai 201913, China）

 

Abstract:Hull base impedance has important influence on the performance of vibration isolation device. To solve the issue that the base of the ship’s pump set double-layer vibration isolation device has excessive vibration response, an effective measure of strengthening the local structure of inner bottom plate is proposed after sea trial and finite element analysis. The result proved that the local hull structure can influence the performance of vibration isolation device, which provides the basis and design method for local hull structure strengthening.

Key words:double-layer vibration isolation system; vibration isolation effect; local hull structural strength

 

 

 

Analytical Oscillation Analysis of the Offshore

Semi-Enclosed Circular Harbor

 

DUAN Jinhui, CHENG Jiansheng, YANG Jiulin, CHU Yuchuan

（College of Field Engineering, Army Engineering University, Nanjing 21007, China)

 

Abstract: In order to study the mechanism and characteristics of offshore semi-enclosed circular harbors, the wave diffraction theory around arc structures is introduced to establish the theoretic calculation model. The harbor is assumed to be made of rigid and vertical thin impenetrable walls and the water depth is assumed constant. The arc of the harbor is extended to form a virtual cylinder, which divides the flow field into the inner and outer regions. The Helmholtz equation is used as the governing equation, which is expanded by its eigen-functions and matched at the common boundaries. The matching principle is that the velocity and pressure should be continuous at the common boundaries to obtain a set of the analytical wave equations under the condition of variable parameters of incident wave angle and entrance opening angle using the series representations. The theoretical model is extended from single-entrance type to multiple-entrance type. The accuracy of the theoretical model is validated by comparing the analytical results with theoretical solutions of the enclosed circular harbor and previous research outcomes.

Key words:harbor oscillation; semi-closed region; wave diffraction; eigen-function

 

 

 

Analysis and Optimization of Window-Related Structural Design in Public Space of Ropax Vessel

 

SHEN Bo¹, ZHAO Yong², YIN Xingjie², JI Chunzheng², WANG Jun²

（1. China Merchants Industry Holdings Co., Ltd., Shenzhen 518000, China;

2. China Merchants Cruise Research Institute (Shanghai) Co., Ltd., Shanghai 200137, China)

 

Abstract:Window-related structure is one of the difficult and critical points in the structural design of Ropax vessel. Based on the experience of window related structural design of a Ropax project, the critical design points are summarized and analyzed, and how to reduce the contribution of window area in way of shell plate to hull girder strength is discussed, then some solutions are proposed to provide reference to the window related structural designers of similar ships.

Key words:window-related structural design; Ropax structural design; hull girder strength

 

 

 

Design of External Fire-Fighting System for

Modern Fire-Fighting Ship

 

JIA Rongping

（Shanghai Bestway Marine Engineering Design Co., Ltd., Shanghai 201612, China）

 

Abstract: The land-based fire-fighting facilities are often affected by the traffic and the loading capacity of the fire extinguishing agent when putting out a fire in coastal petrochemical plants or on the ships at coastal wharves. This paper discusses the function, composition and design innovation of external fire-fighting system for modern fire-fighting ships based on Yang Pu 1200t offshore fire-fighting shipPu Xiao 1, and elaborates the key points in the installation design of the fire-fighting system to provide reference for the design of subsequent ships of the same type. The successful delivery of Pu Xiao 1 is an embodiment of large-scale, diversified and centralized development of fire-fighting ships, which provides new ideas for the design of coastal fire-fighting facilities.

Key words:fire-fighting ship; external fire-fighting system; foam extinguisher; dry powder extinguisher; CO₂ extinguisher

 

 

 

Selection of Start Method for Marine Bulk-Power Emergency Loads

 

CAO Zhengyu, ZHOU Ting

（Shanghai Waigaoqiao Shipbuilding Co., Ltd., Shanghai 200137, China）

 

Abstract:The capacity restriction of emergency generator makes the impact caused by the startup of bulk-power emergency load on power grid particularly prominent. In order to solve the problem from the theoretical perspective, this paper discusses the issues to be considered in selecting the start method of bulk-power emergency consumers. A real case is taken to introduce how to choose the start method to provide reference for the marine electrical designers. The proper selection of start method of bulk-power emergency load can not only guarantee the safe operation of the ship, but also avoid the increase of ship construction cost due to the increase of emergency generator capacity.

Key words:transient voltage drop; sudden addition characteristics; start in sequence; starting torque

 

 

 

Study of the Characteristics of Marine Sound Absorbing Materials

Based on Numerical Simulations

 

GU Saiwen¹, NING Changqing¹, ZHOU Yuwen^2,3, ZHANG Zhaode^2,3

（1. Zhoushan Wonderful Marine Design Co., Ltd., Zhoushan 316021, China;

2. School of Naval Architecture and Mechanical-electrical Engineering,

ZhejiangOcean University, Zhoushan 316022, China;

3. Key Laboratory of Offshore Engineering Technology of Zhejiang Province, Zhoushan 316022, China)

 

Abstract: This paper uses numerical simulation methods to study the characteristics of composite material, which have the effect on ship noise, such as porosity, material thickness and material laying methods. By changing the property assignment of the material and analyzing the noise variation of the cabin, it is found that the noise value does not change linearly with the change of material porosity and thickness. The result shows that the composite material will have the best peak value of noise reduction as the porosity and thickness of the rock wool change. When the material is been laying, the sound absorption effect of the outermost constituent of the composite material largely determines the overall noise reduction effect and the extra layers of the material have almost no effect on the noise values.

Key words:marine noise; porosity; sound absorbing material; numerical simulation

 

 

 

Informatization, Digitization and Intelligentization Promote the Transformation of Shipping Operation Service System

 

DING Jun¹, LI Xin², HUANG Jiantao²

（1.China Merchants Energy Transportation Co., Ltd., Shenzhen 518000, China;

2. Shanghai Merchant Ship Design & Research Institute, Shanghai 201300, China）

 

Abstract:This paper systematically elaborates the specific connotation and significance of informatization, digitalization and intelligentization based on the smart ships and the operation data to promote the transformation of the shipping operation service system. It introduces the research status of marine informatization, digitalization and intelligentization at home and abroad, and summarizes the practices in the transformation of shipping operation service system. Practice shows that informatization, digitalization and intelligentization can be combined to effectively promote the transformation of shipping operation service system. At this basis, the direction of future development is proposed.

Key words:informatization; digitalization; intelligentization; operation service

 

 

 

A Study on the Damaged Conditions in Structural Strength

Assessment of Container Ships

 

XU Min, TANG Mingwen, WANG Gang

（Rules & Technology Center, CCS, Shanghai 200135, China)

 

Abstract: Container ships, no matter intact or damaged, must satisfy the safety and environmental requirements when operating under the prescribed operational and environmental conditions. Therefore, the effective assessment of the damaged hull structures is important to ensure ship's safety. Using the finite element method for hull section, the yielding and buckling strength of the primary structures are evaluated by comparing the stress response of the structures under different damaged states to establish the evaluation method for damage condition. The research results show that the method is reasonable and conductive to structural safety and optimization design of container ships.

Key words:container ship; damage; finite element method; strength assessment

 

 

 

Design Process of Safe Return to Port and

Its Control Point for Ropax

 

TIAN Zhengjun, WU Lin, JI Chunzheng

（China Merchants Cruise Research Institute (Shanghai) Co., Ltd., Shanghai 200137, China）

 

Abstract:Ropax has the dual function of passenger ship and cargo carriers, so it must satisfy the requirements on Safe Return to Port (SRtP). A Ropax ship is taken as the example to explain the complete process of SRtP design, construction and verification in detail along with the control points for each stage to provide reference for the design and construction of similar ships.

 

Key words:Ropax; Safe Return to Port; design process; control key