Analysis on the Longitudinal Bending Strength of Cruise Ship

 

LU Chun-hui¹, SHI Gui-jie², PENG Wen-ke¹, ZHENG Gang¹, GU Ya-juan¹

(1. Shanghai Rules and Research Institute, China Classification Society, Shanghai 200135, China;

2a. State Key Laboratory of Ocean Engineering; 2b. School of Naval Architecture; 2c. Ocean and Civil Engineering,

China Strategy Institute of Ocean Equipment Engineering, Shanghai Jiao Tong University, Shanghai 200240, China)

 

Abstract: This paper studies the stress distribution of longitudinal hull girder, the superstructure effectiveness and the longitudinal strength assessment method of cruise ships according to both the Rules for Cruise Ships issued by China Classification Society (CCS) and the actual ship validation in order to guide the application of the rules. The major distinctions of the cruise ship from other ship types are recognized through the analysis of hull structural characteristics, which also derives the key points for the longitudinal strength analysis of cruise ships. The longitudinal bending stress and shear stress distribution pattern are analyzed based on the direct calculation method specified by the Rules for Cruise Ships, so as to summarize the main factors of the preliminary design and the variation characteristics of the superstructure effectiveness. An effective method for the assessment of longitudinal strength with consideration on the superstructure effectiveness is proposed on the basis of the beam theory.

Key words:cruise ship; longitudinal strength; superstructure effectiveness

 

 

 

Numerical Simulation and Analysis of Stress Distribution Around Cutouts of Double Bottom Rib Plate

 

DING Yun-lai¹, WANG Wei², KE Li³

(1. Cheng Xi Shipyard Co., Ltd., Jiangyin 214433, China;

2. Jiangnan Shipbuilding (Group) Co., Ltd., Shanghai 201913, China;

3. School of Naval Architecture and Ocean Engineering,

Jiangsu University of Science and Technology, Zhenjiang 212003, China)

 

Abstract: Ship’s hull structure undergoes fluctuating actions of the combined loads of longitudinal bending, external water pressure and cargo loads while sailing, which could lead to stress concentration around the cutouts and cause further structural fatigue damages. This study carries out the hole-edge stress analysis of the hull structure cutouts under typical loads, where the finite element simulations of hole-edge stress distribution of the cutouts on the double bottom structure under typical bending and compression loads are performed to analyse the effect of reinforced structures on the stress distribution around the cutouts. It may provide reference for the design optimization of hull structure’s cutouts.

Key words:cutout; hole-edge stress; bending load; compression load; finite element analysis

 

 

 

Stress Feature and Pressure Test of

Conical Edge Spherical Crown Type Acrylic Observation Window

 

YANG Qing-song, JIANG Lei

(China Ship Scientific Research Center, Wuxi 214082, China)

 

Abstract: The preliminary design of a conical edge spherical crown type acrylic observation window is fulfilled according to the acrylic window design handbook. The theoretical formula for its structure stress is proposed according to the geometric form and force conditions, and then the design optimization is carried out based on the formula. A full scale prototype of the observation window is built and tested in the pressure tank where its stress and ultimate load are monitored in real-time to validate the theoretical structure stress and ultimate load calculations.

Key words:conical edge spherical crown type acrylic observation window; structure stress; ultimate load; design optimization; pressure tank test

 

 

 

Analysis on the Residual Ultimate Strength of Cabin Section After

Strength Deck Damage Deformation Due to Non-Contact Explosion

 

XU Hao-ran¹，ZHANG Shi-lian¹，LI Cong²

(1. School of Naval Architecture Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

2. Marine Design & Research Institute of China, Shanghai 200011, China)

 

Abstract: According to the hull structural design concept of adding longitudinal box girder to the strength deck as adopted on German Sachsen-class frigates, this study evaluates the increased protection ability of the strength deck for non-contact explosion after implementing the longitudinal box girder. The impact load of non-contact explosion and the CONWEP module in ABAQUS are used to simulate the impact forces of non-contact explosion on the strength deck. Two finite element models of the cabin sections after strength deck damage are created: one is strengthened with the longitudinal box girder and the other not. Their residual ultimate strengths are solved by the quasi-static method. Trigonometric series are used to fit the deformation curve of the strength deck at midship. Then the parameters to describe the deformation of the strength deck are obtained, and their relations with the holding ability of the residual ultimate strength are analyzed. When the longitudinal box girder is added to the proper positions of the strength deck, the analysis shows an obvious result that the strengthened cabin section has the effectively improved hull residual ultimate strength compared with the un-strengthened cabin section which has the same deformation parameters for the strength deck.

Key words:box girder; residual ultimate strength; non-contact explosion; strength deck deformation; trigonometric series

 

 

 

Structural Design of Small Liquefied Gas Carrier

 

CHANG Shi-wei, LOU Chun-jing, ZHANG Wei, WANG Zhi-yuan

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

 

Abstract: Small liquefied gas carriers are maneuverable in navigation, flexible in feeder scheduling, seldom restricted by water depth and bridge clearance, and suitable for transporting flammable chemicals of extremely low temperature, so there are broad prospects for development. The key technologies for the kind of ship are analyzed through interpretation of IGC Code and the rules & regulations of the classification societies. A 22000m³ liquefied gas carrier with type C bi-lobe tank is taken as the target ship to discuss the structural design from five aspects, in order to provide reference for the design of similar ship types.

Key words:liquefied gas carrier; key technologies; structural design; bi-lobe tank

 

 

 

Anti-Rolling Tank Design for AHTS

 

ZHANG Ya-ming

(Shanghai Zhenhua Heavy Industries Co., Ltd., Shanghai 200125, China)

 

Abstract: To improve the comfort and safety of the crew and to increase ship operation efficiency, a rectangular anti-rolling tank is designed for the Anchor Handling Tug Supply (AHTS) vessel to reduce roll amplitude, increase roll period and decrease green water on deck so as to improve the sea-keeping performance of the ship. This paper elaborates the mechanical model and design principles of the rectangular anti-rolling tank, and proposes a design that can adjust the tank water level automatically. The anti-rolling tank model test and the ship model test in the basin have validated the effectiveness of the anti-rolling tank in improving the ship’s seakeeping performance. Data collection for the anti-rolling system during sea trial also confirms that the proposed design with automatic water level adjustment is successful.

Key words:seakeeping; roll reduction; anti-rolling tank; ship model test; sea trial data

 

 

 

A Sea-Sky-Line Detection Method based on

Retinex Algorithm for Unmanned Surface Vessel

 

WANG Chuan-long, MA Shan-wei, QU Chong

(Shanghai Marine Diesel Engine Research Institute, Shanghai 201108, China)

 

Abstract: The detection of sea-sky-line plays an important role in the automatic cruise and target recognition of unmanned surface vessels (USVs). This paper proposes a sea-sky-line detection method for USVs based on Retinex algorithm and Hough transform, where Retinex algorithm is used to enhance the RGB image of sea-sky background; the median filtering, threshold segmentation, morphological closing operation and Canny operator are used to extract the edge; and Hough transform is used to extract the sea-sky-line. The result of MATLAB simulations shows that the proposed algorithm can accurately extract the sea-sky-line from complex background and has a good adaptability.

Key words:unmanned surface vessel; sea-sky-line detection; Retinex algorithm; threshold segmentation; Hough transform

 

 

 

Selection Principle and Installation of

SCR System on Ocean-Going Ship

 

YIN Hua-bing, WANG Wei-bin

(COSCO SHIPPING Specialized Carriers Co., Ltd., Guangzhou 510623, China)

 

Abstract: This paper studies the ship exhaust gas emission system in accordance with the stricter requirements of MARPOL Annex VI issued by the International Maritime Organization (IMO) on ship exhaust gas (mainly NO_x and SO_x) emission. The selection principles of NO_x exhaust gas treatment systems for ocean-going ships are analyzed. The status quo of NO_x exhaust gas treatment technologies as well as the advantages and disadvantages of relatively mature technologies available at the moment are compared. On this basis, an overall solution of low sulfur fuel plus low pressure selective catalytic reduction (LP-SCR) technology is proposed, which is applied to ships now. The paper also looks into the future development trend in this field to provide references.

Key words:MARPOL Annex VI; ship’s exhaust gas treatment system; selection principle; low sulfur fuel oil +LP- SCR

 

 

 

Application Design of Variable Frequency Drive System

 

WANG Ke-hu, TIAN Qing-ming, CHEN Lin

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

 

Abstract: This paper briefly introduces the requirements for the design and the equipment selection and installation of Variable Frequency Drive (VFD) system, and discusses why VFD systems generate harmonic waves and how to eliminate the influence of harmonic waves in ship operation. The selecting and laying of cables are elaborated in detail, which is a key point to pay more attention in the onboard applications. The voltage transformer, frequency transformer, equipment sealings and terminal connection processing of the VFD system are introduced briefly. The equipment in the VFD system are interlinked, any unsatisfactory equipment selection or installation will lead to unpredictable influence. The comprehension of VFD system design and application can provide reference for wider applications in the future.

Key words:Variable Frequency Drive; voltage transformer; odd harmonic; cable laying; equipment sealing

 

Application of 3D Laser Scanning Technology in

Ship Line-heating Measurement

 

ZHAO Hua, LI Liang, LI Cun-jun, WANG Hai-rong, ZHANG Ying, YE Xian-huai

(Zhoushan Institute of Calibration and Testing for Quality and Technical Supervision, Zhoushan 316021)

 

Abstract: This paper introduces the principles and procedures of ship line-heating test based on 3D laser scanning technology. The Gaussian curvature is used as the evaluation basis, and the actual measurement data of the ship’s shell plate frame line are compared with the design data one by one to calculate and evaluate the degree of surface formation, so as to complete the forming examination of the line-heating. It is proved through experiment that the technology can effectively realize the forming examination and evaluation of line-heating, and assist to keep the forming error under control.

Key words:line-heating; Gaussian curvature; 3D laser scanning

 

 

 

Prediction and Control of Welding Induced Buckling

in Reinforced Thin Plate Ship Structure

 

WANG Jiang-chao^1,2，YI Bin¹，ZHOU Hong³

（1.    School of Naval Architecture and Ocean Engineering, Huazhong University of Science and Technology,

Wuhan 430074, China; 2. Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration,

Shanghai 200240, China; 3. School of Naval Architecture and Ocean Engineering,

Jiangsu University of Science and Technology, Zhenjiang 212003, China）

 

Abstract: High Tensile Strength Steel (HTSS) can effectively reduce ship’s structure lightweight, but the shrinkage force near the weld seam during welding assembly may induce buckling. T-type welding joint is taken as the research object, and the thermal elastic-plastic finite element analysis and large deformation theory are adopted to predict the welding induced buckling, deformation caused by buckling and critical conditions of buckling. Corresponding control measures are also proposed in the paper.

Key words:welding induced buckling; inherent deformation; eigenvalue analysis; intermittent zigzag welding

 

 

 

Heterogeneous Data Collaboration and Unified Data

Source for Hull Production Design

 

QIAN Huai-yu，CAI Lu，LENG Jiu-ping

(Shanghai Tresin Information Technology Company Ltd., Shanghai 200011, China)

 

Abstract: Heterogeneous data collaboration and unified data source are important prerequisites to guarantee the accuracy of data flow. This paper discusses typical issues concerning the data collaboration and the unified data source in the hull production design according to the characteristics of the ship design and construction in China and proposes solutions for the specific problems of data collaboration and management in using Tribon M3 software.

Key words:hull production design; heterogeneous data; data collaboration; unified data source

 

 

 

A Research on Ship Structure Drawing Technique

Based on 3D Experience Platform

 

ZOU Meng-yao¹, WU Li², WANG Chong¹, GUAN Wei-yuan¹

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

2. Huazhong Research Institute of Optoelectronic Technology, Wuhan National Laboratory for Opto-Electronics, 

Wuhan 430200, China）

 

Abstract: Ship structure drawing is one of the most important procedures in 3D design and plays an important role in the early stage of 3D design. A research is thus carried out to produce a ship structure drawing method based on the template configuration scheme of Generative View Style (GVS) in the Dassault system, where the requirements for ship structure drawings are taking into account. An outlook on the developing trend of the technique is also depicted in the paper.

Key words:3D Experience platform; ship structure drawing; GVS template; resource library

 

 

 

Research and Development of

Securing Checking System for Large Container Ship

 

HU Min

(China Shipbuilding NDRI Engineering Co., Ltd., Shanghai 200063, China)

 

Abstract: To improve the efficiency of securing checking for large container ships, this study establishes a general model suitable for computer operation and develops a securing checking system with the in-depth analysis on the forces of container ship lashing bridge and lashing bars. The system provides complete solutions from graphical modelling to securing checking, with the functions of parametric modelling and one-button checking, which is easy to use, good in performance, scaled to support the largest container ship in the world, and adequate for the rule calculations of classification societies. It significantly improves the efficiency of securing checking on container ship, brings notable economic benefits to the customers, and provides strong data support for the design optimization of related products.

Key words:securing of container; lashing bridge; lashing bar; securing effectiveness check