• Title/Summary/Keyword: ship structure

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Study on three-dimensional numerical simulation of shell and tube heat exchanger of the surface ship under marine conditions

  • Yi Liao;Qi Cai;Shaopeng He;Mingjun Wang;Hongguang Xiao;Zili Gong;Cong Wang;Zhen Jia;Tangtao Feng;Suizheng Qiu
    • Nuclear Engineering and Technology
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    • v.55 no.4
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    • pp.1233-1243
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    • 2023
  • Shell-and-tube heat exchanger (STHX) is widely used by virtue of its simple structure and high reliability, especially in a space-constrained surface ship. For the STHX of the surface ship, roll, pitch and other motion of the ship will affect the heat transfer performance, resistance characteristics and structural strength of the heat exchanger. Therefore, it is urgent to carry out numerical simulation research on three-dimensional thermal hydraulic characteristics of surface ship STHX under the marine conditions. In this paper, the numerical simulation of marine shell and tube heat exchanger of surface ship was carried out using the porous media model. Firstly, the mathematical physical model and numerical method are validated based on the experimental data of a marine engine cooling water shell and tube heat exchanger. The simulation results are in good agreement with the experimental results. The prediction errors of pressure drop and heat transfer are less than 10% and 1% respectively. The effect of marine conditions on the heat transfer characteristics of the heat exchanger is investigated by introducing the additional force model of marine condition to evaluate the effect of different motion parameters on the heat transfer performance of the heat exchanger. This study could provide a reference for the optimization of marine heat exchanger design.

Multi-Input Multi-Output Nonlinear Autopilot Design for Ship-to-Ship Missiles

  • Im Ki-Hong;Chwa Dong-Kyoung;Choi Jin-Young
    • International Journal of Control, Automation, and Systems
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    • v.4 no.2
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    • pp.255-270
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    • 2006
  • In this paper, a design method of nonlinear autopilot for ship-to-ship missiles is proposed. Ship-to-ship missiles have strongly coupled dynamics through roll, yaw, and pitch channel in comparison with general STT type missiles. Thus it becomes difficult to employ previous control design method directly since we should find three different solutions for each control fin deflection and should verify the stability for more complicated dynamics. In this study, we first propose a control loop structure for roll, yaw, and pitch autopilot which can determine the required angles of all three control fins. For yaw and pitch autopilot design, missile model is reduced to a minimum phase model by applying a singular perturbation like technique to the yaw and pitch dynamics. Based on this model, a multi-input multi-output (MIMO) nonlinear autopilot is designed. And the stability is analyzed considering roll influences on dynamic couplings of yaw and pitch channel as well as the aerodynamic couplings. Some additional issues on the autopilot implementation for these coupled missile dynamics are discussed. Lastly, 6-DOF (degree of freedom) numerical simulation results are presented to verify the proposed method.

Network-based Simulation System Framework for the Safety Assessment of Ship and Visualization Method (네트워크 기반 선박 안전성 평가 시뮬레이션 시스템 프레임워크 및 가시화)

  • Lee, Kyung-Ho;Kim, Hwa-Seop;Oh, June;Park, Jong-Hoon
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.5 s.149
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    • pp.619-629
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    • 2006
  • The safety assessment of the structure related to people has become the most important part in the process of the design. Especially, in the case of a ship, as regulations about the safety of passengers and the pollution in the ocean are strictly reinforcing, the safety assessment has become the most important part in the process of the design. In this paper, we suggested network-based simulation system framework using HLA (High Level Architecture) among many kind of simulations to assess the safety of the ship. In addition, the visualization method which is composed of graphic user interface for ship modeling and the visualization of ship motion is presented.

A Study of Product Information Quality Verification in Database Construction of Naval Ship Product Models (실적선 데이터베이스 구축을 위한 함정 제품모델의 데이터 품질검증에 관한 연구)

  • Oh, Dae-Kyun;Shin, Jong-Gye;Choi, Yang-Ryul
    • Journal of the Society of Naval Architects of Korea
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    • v.46 no.1
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    • pp.57-68
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    • 2009
  • In automotive industries, reusability of product information is increasing through database construction of previous product data. The product data is stored by data quality management in product information systems. For naval ships, have the functional similarity by the ships of the same classification and class, that are built by series. Information of hull structures as well as embarked equipments are similar. So it would be effective to use database systems that are considered product information quality of previous ships in design and production processes. In this paper we discuss product information quality in database construction of naval ship product models. For this, we propose a basic concept and reference model for data quality verification. Based on this concept, A verification guideline is defined and it is applied for the case study of the digital naval ship which was built to the naval ship product model.

Development of NASTRAN-based Optimization Framework for Vibration Optimum Design of Ship Structure. (선박 구조물의 진동 최적설계를 위한 NASTRAN 기반 최적화 프레임웍의 제안)

  • Kong, Y.M.;Choi, S.H.;Chae, S.I.;Song, J.D.;Kim, Y.H.;Yang, B.S.
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.11 s.104
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    • pp.1223-1231
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    • 2005
  • Recently, the issue of ship nitration due to the large scale, high speed and lightweight of ship is emerging. For pleasantness in the cabin, shipbuilders are asked for strict vibration criteria and the degree of nitration level at a deckhouse became an important condition for taking order from customers. This study proposes a new optimization framework that is NASTRAN external call type optimization method (OptShip) and applies to an optimum design to decrease the nitration level of a deckhouse. The merits of this method are capable of using of global searching method and selecting of various objective function and design variables. The global optimization algorithms used here are random tabu search method which has fast converging speed and searches various size domains and genetic algorithm which searches multi-point solutions and has a good search capability in a complex space. By adapting OptShip to full-scale model, the validity of the suggested method was investigated.

Research on systematization and advancement of shipbuilding production management for flexible and agile response for high value offshore platform

  • Song, Young-Joo;Woo, Jong-Hun;Shin, Jong-Gye
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.3 no.3
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    • pp.181-192
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    • 2011
  • Recently, the speed of change related with enterprise management is getting faster than ever owing to the competition among companies, technique diffusion, shortening of product lifecycle, excessive supply of market. For the example, the compliance condition (such as delivery date, product quality, etc.) from the ship owner is getting complicated and the needs for the new product such as FPSO, FSRU are coming to fore. This paradigm shift emphasize the rapid response rather than the competitive price, flexibility and agility rather than effective and optimal perspective for the domestic shipbuilding company. So, domestic shipbuilding companies have to secure agile and flexible ship production environment that could respond change of market and requirements of customers in order to continue a competitive edge in the world market. In this paper, I'm going to define a standard shipbuilding production management system by investigating the environment of domestic major shipbuilding companies. Also, I'm going to propose a unified ship production management and system for the operation of unified management through detail analysis of the activities and the data flow of ship production management. And, the system functions for the strategic approach of ship production management are investigated through the business administration tools such as performance pyramid, VDT and BSC. Lastly, the research of applying strategic KPI to the digital shipyard as virtual execution platform is conducted.

Dynamic Response of Container Ship Subjected to Bow flare Slamming Loads

  • Choi, Tae-Soon;Islam, MD Shafiqul;Seo, Dae-Won;Kim, Joon-Gyu;Song, Kang-hyun
    • Journal of Advanced Research in Ocean Engineering
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    • v.4 no.4
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    • pp.195-203
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    • 2018
  • The wave impact on ships could cause local damage to the ship's hull, which has been a concerning issue during the ship design process. In recent years, local structural damages of ships caused by slamming loads have been reported by accident; therefore, it is necessary to study the local slamming pressure loads and structural response assessment. In the present study, slamming loads around the ship's bow region in the presence of regular wave have been simulated by RANS equations discretized with a cell-centered finite volume method (FVM) in conjunction with the $k-{\Box}$ turbulence model. The dynamic structural response has been calculated using an explicit FE method. By adding the slamming pressure load of each time step to the finite element model, establishing the reasonable boundary conditions, and considering the material strain-rate effects, the dynamic response prediction of the bow flare structure has been achieved. The results and insights of this study will be helpful to design a container ship that is resistant enough to withstand bow flare slamming loads.

Development of Structural Analysis System for a Ship Block under Lifting and Turnover Operation (선박 블록의 반전 및 이동시 변형예측을 위한 구조해석 시스템의 개발)

  • Han, Jeong-Sam;Lee, Won-Jae;Choo, Yeon-Seok;You, Young-Kyoon;Kwak, Byung-Man
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.219-223
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    • 2001
  • This paper introduces DS/Block-Structure - a structural analysis module of DS/Block, which is a Design System to simulate the behavior of a ship block in various crane operations and to evaluate its structural deformation using the finite element method. It runs based on a CAD program, Pro/ENGINEER, and structural analyses are performed by a developed FE code. Boundary conditions for the FE analysis of a ship block under lifting and turnover operation are also considered.

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A Study on the fatigue strength analysis of the welded joints in ship hull construction (선체구조의 용접이음부의 피로강도 해석법에 관한 연구)

  • 엄동석;강성원;이성구;김원범
    • Journal of Welding and Joining
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    • v.10 no.4
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    • pp.259-267
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    • 1992
  • In this report, a method to predict the fatigue strength in welded structure member of ship construction is studied considering the effects of statistical characteristics of mild steels and weld toe shapes on the fatigue crack initiation life. The fatigue test under pulsating bending load is carried out with the model specimens of the web frame in double bottom of ship hull. The propriety of the fatigue life curve with probability of failure in the transverse strength members of ship hull construction is confirmed by the comparison with the results of fatigue test on the model of the various transverse strength members.

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Strength Evaluation for Adhesive Bonds of Adhesive with FRP Ship Body Structure (FRP 선체구조용 접착제의 접착강도 평가)

  • Ahn, Seok-Hwan;Choi, Han-Kyu;Nam, Ki-Woo
    • Journal of Ocean Engineering and Technology
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    • v.24 no.1
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    • pp.146-152
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    • 2010
  • Recently, the applied frequency of composite materials was increased from the viewpoint of lightweight, high strength and low cost when a leisure boat and a fishing boatwere built. However, studies on the mechanical properties of composite material with ship are rare. Specially, a leisure boat and fishing boat with FRP had been built by hand lay-up method. However, the vacuum infusion method is rising recently for ship building. The manufactured these FRP plates were combined by using the adhesive. Therefore, in this study Cleavage peel strength, Shear strength and fatigue limit of adhesive bonds by tensileloading were estimated. From test results, the strengths of FRP specimens made by the vacuum infusion method are higher than that of the hand lay-up method.