The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Xingke Zhao - One of the best experts on this subject based on the ideXlab platform.
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phase evolution and mechanical properties of coarse grained heat affected zone of a cu free high strength low alloy Hull Structure steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Shi Dong, Jihua Huang, Jiang Yang, Shuhai Chen, Xingke ZhaoAbstract:Abstract Weldability of a Cu-free high strength low alloy (HSLA) Hull Structure steel is studied. Strengthening contributions of this steel are analyzed and phase continuous cooling transformation in simulated coarse-grained heat affected zone (CGHAZ) is investigated. Indeed, strengthening contributions of simulated CGHAZs under heat input 50 and 20 kJ/cm, respectively, are estimated. It shows this Cu-free HSLA Hull Structure steel is dominated at grain refinement strengthening and supplemented by precipitation strengthening and phase transformation strengthening, while the simulated CGHAZ under heat input 50 or 20 kJ/cm is dominated at phase transformation strengthening and supplemented by solid solution strengthening and grain refinement strengthening. The drawn simulated heat affected zone continuous cooling transformation (SH-CCT) diagram shows this Cu-free HSLA Hull Structure steel can obtain main lath-like microStructures in a wide cooling rate range with low phase start temperature. Mechanical property tests of simulated CGHAZ samples indicate high strengths and good low temperature impact toughness. All results exhibit this Cu-free HSLA Hull Structure steel has satisfactory weldability, which suggests its wide potential applications.
Kyuyeul Lee - One of the best experts on this subject based on the ideXlab platform.
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Development of a mobile welding robot for double-Hull Structures in shipbuilding
Journal of Marine Science and Technology, 2010Co-Authors: Ju-hwan Cha, Kyuyeul Lee, Taewan Kim, Jongwon Kim, Donghun LeeAbstract:This paper describes the development of a self-driving mobile welding robot. The robot is used to weld U-shaped welding areas in enclosed double-Hull Structures. In order to place itself inside the double-Hull Structure, the robot is capable of passing through an access hole 600 mm wide and 800 mm high. This research addresses the mechanical and control systems of the robot. The mechanical system of the robot consists of an eight-axis mobile platform, and a six-axis welding unit. The control system consists of a main controller, a welding machine controller (arc sensor board), and seam tracking sensors, i.e., a touch sensor, a laser sensor, and an arc sensor. To reduce the number of cables that would be dragged by the welding robot, the main controller is designed as an embedded type that is mounted on the back of the mobile platform.
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Rail Running Mobile Welding Robot ‘RRX3’ for Double Hull Ship Structure
IFAC Proceedings Volumes, 2008Co-Authors: Jongwon Kim, Kyuyeul Lee, Taewan Kim, Donghun Lee, Sungcheul Lee, Chaemook Lim, Sung-won KangAbstract:Abstract ‘Seoul National University’ and ‘Daewoo Shipbuilding & Marine Engineering’ in Korea jointly developed a mobile welding robot, the ‘Rail Runner’ (RRX), which is able to freely move in both transverse and longitudinal directions, and perform welding tasks in double Hull Structures. Recently, RRX2, (the second version of RRX), was presented at ‘Robotics and Applications 2007'. In this paper, the design, manufacturing, and application of RRX3, the third version of RRX, is described. The moving mechanism of RRX, which is able to move freely in a double Hull Structure, has two functions. 1) To move in a longitudinal direction by driving wheels using longi. faces as ‘rails', and 2) To move in a transverse direction by sliding along supporting longi. faces using extension arms. The body of the RRX3 is composed of a 12-axis, 6-axis mobile platform that supports the RRX moving mechanism and a 6-axis welding robot to do the welding job. The main point in designing RRX3 is to make it capable of passing through a 600mm×800mm sized access hole, the entrance into an enclosed double Hull Structure. The full size of the manufactured RRX3 is 1825mm×495mm×569mm, and thus the RRX3 is able to pass through an access hole. The weight is 250kg with a 6-axis mobile platform, 6-axis welding robot, and mounted controller.
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modularized control architecture of an embedded controller for mobile welding robot in the shipyard
IFAC Proceedings Volumes, 2008Co-Authors: Kyuyeul Lee, Taewan Kim, Jongwon Kim, Heonyoung Lim, Jongjin Woo, Sang Moo Lee, Sooho KimAbstract:The present study describes the development of controller hardware and control software for a mobile welding robot, which can move in the transverse and longitudinal directions (Moving Tasks), perform the welding tasks of the U-shaped parts and bracket parts in a double Hull Structure (Welding Tasks), and detect points of the welding path (Sensing Tasks). Controller hardware consists of a main controller and a welding machine controller. The main controller, which is mounted on the mobile welding robot, consists of a CPU board, a motion controller, and an incremental encoder type AC servo motor driver. The welding machine controller, which is mounted on the welding machine located on the outside of the double Hull Structure, controls the welding machine. Communication between the two controllers is made via the RS485. Control software consists of 4 layers: Task Manager, Task Planner, Actions for Task, and Task Executer. Each Layer consists of modules such as the Action Module, Motion Generator Module, Servo Module, etc. Suitable combinations of modules enable the control software to perform the required tasks. Control software is developed using C programming under QNX Operating System, which is well known to have a reliable hard-realtime performance.
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an initial Hull structural modeling system for computer aided process planning in shipbuilding
Advances in Engineering Software, 2006Co-Authors: Myungil Roh, Kyuyeul LeeAbstract:At the initial stage of ship design, it is difficult for designers to define all design information of a Hull Structure on 2D drawings. Thus, other designers must undertake the arduous task of translating such information to generate a 3D CAD model of the Hull Structure which is required at the following design stage such as the initial process planning stage. Since this task needs much time and effort, the 3D CAD model is not being generated at the initial design stage. For solving this problem, an initial Hull structural modeling system is developed in this study. The applicability of the developed system is demonstrated by applying it to a deadweight 300,000 ton VLCC (Very Large Crude oil Carrier). The results show that the developed system can quickly generate the 3D CAD model of the Hull Structure and accurately extract the production material information for computer-aided process planning at the initial design stage.
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rapid pipe modeling method considering the relationship with a Hull Structure
Journal of The Society of Naval Architects of Korea, 2006Co-Authors: Myungil Roh, Woo-young Choi, Kyuyeul LeeAbstract:The present piping modeling method requires detailed inputs from a designer to generate a piping model, and thus it takes much time for the designer to perform such task. Moreover, the piping model has no relation with that of Hull Structure. Thus, it is time-consuming and requires much effort if design changes arise. In this study, a method that generates quickly many pipes using a pipe tray and a conversion method that converts automatically the pipes into objects related with the Hull Structure are proposed. A piping modeling system based on the proposed methods is developed. The applicability of the developed system is demonstrated by applying it to the generation of the piping model of a deadweight 300,000ton VLCC(Very Large Crude oil Carrier). The results show that the developed system can quickly generate the piping model in relation with the Hull Structure.
Myungil Roh - One of the best experts on this subject based on the ideXlab platform.
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improvement of ship design practice using a 3d cad model of a Hull Structure
Robotics and Computer-integrated Manufacturing, 2008Co-Authors: Myungil Roh, Woo-young Choi, Seongji YooAbstract:At the initial stage of ship design, a Hull structural model, that is, a 3D CAD model of a Hull Structure is not generated by the existing shipbuilding CAD system because it is time-consuming and requires much effort. Without the Hull structural model, a designer must manually calculate the production material information of a building block by using 2D drawings, parent ship data, and design experiences at the initial planning and scheduling stages. At the initial stage of Hull structural analysis, the designer manually generates a structural analysis model, that is, a finite element model of the Hull Structure. Moreover, the piping model, that is a 3D CAD model of the pipes in the Hull Structure, is generated independently of the Hull structural model at the detailed design stage. To lighten the burden imposed on the designer, we developed an initial Hull structural modeling system in our previous study. Using this system, a designer can rapidly and easily generate the Hull structural model at the initial stage of design. In this study, the generation methods of the production material information of a building block, the structural analysis model, and the piping model based on the Hull structural model are developed. The applicability of the developed methods are demonstrated by applying them to a deadweight 300,000 ton very large crude oil carrier (VLCC). The results show that the developed methods can quickly generate the corresponding information or models at the initial design stage.
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generation of the 3d cad model of the Hull Structure at the initial ship design stage and its application
Computers in Industry, 2007Co-Authors: Myungil RohAbstract:Currently, all design information of a Hull Structure is being first defined on 2D drawings not 3D CAD model at the initial ship design stage and then transferred to following design stages through the 2D drawings. This is caused by the past design practice, limitation on time, and lack of shipbuilding CAD systems supporting the initial design stage. As a result, the following design tasks such as the process planning and scheduling are being manually performed using the 2D drawings. For solving this problem, a data Structure for shipbuilding CAD systems supporting the initial design stage is proposed and a prototype system is developed based on the data Structure. The applicability of the system is demonstrated by applying it to various examples. The results show that the system can be effectively used for generating the 3D CAD model of the Hull Structure at the initial design stage.
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an initial Hull structural modeling system for computer aided process planning in shipbuilding
Advances in Engineering Software, 2006Co-Authors: Myungil Roh, Kyuyeul LeeAbstract:At the initial stage of ship design, it is difficult for designers to define all design information of a Hull Structure on 2D drawings. Thus, other designers must undertake the arduous task of translating such information to generate a 3D CAD model of the Hull Structure which is required at the following design stage such as the initial process planning stage. Since this task needs much time and effort, the 3D CAD model is not being generated at the initial design stage. For solving this problem, an initial Hull structural modeling system is developed in this study. The applicability of the developed system is demonstrated by applying it to a deadweight 300,000 ton VLCC (Very Large Crude oil Carrier). The results show that the developed system can quickly generate the 3D CAD model of the Hull Structure and accurately extract the production material information for computer-aided process planning at the initial design stage.
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rapid pipe modeling method considering the relationship with a Hull Structure
Journal of The Society of Naval Architects of Korea, 2006Co-Authors: Myungil Roh, Woo-young Choi, Kyuyeul LeeAbstract:The present piping modeling method requires detailed inputs from a designer to generate a piping model, and thus it takes much time for the designer to perform such task. Moreover, the piping model has no relation with that of Hull Structure. Thus, it is time-consuming and requires much effort if design changes arise. In this study, a method that generates quickly many pipes using a pipe tray and a conversion method that converts automatically the pipes into objects related with the Hull Structure are proposed. A piping modeling system based on the proposed methods is developed. The applicability of the developed system is demonstrated by applying it to the generation of the piping model of a deadweight 300,000ton VLCC(Very Large Crude oil Carrier). The results show that the developed system can quickly generate the piping model in relation with the Hull Structure.
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development of a semantic product modeling system for initial Hull Structure in shipbuilding
Robotics and Computer-integrated Manufacturing, 2004Co-Authors: Kyuyeul Lee, Wonjoon Lee, Myungil RohAbstract:Abstract In the initial stage of ship design, designers represent geometry, arrangement, and dimension of Hull Structures, which correspond to product model information, with 2D geometric primitives such as points, lines, arcs, and drawing symbols on 2D drawings. However, designers must translate the product model information defined on the 2D drawings more intelligently in the following design stages. Thus, design semantics could be lost and design processes that follow could be delayed because of errors by mistranslating the information. Here, design semantics mean design intents of the designer, that is, functions and Structures which the product must have. In this study, a semantic product model data Structure of an initial ship Hull Structure was proposed, and a semantic product modeling system was developed based on the proposed data Structure. The proposed data Structure can store semantic product model information such as product design results with the use of 2D wire frame geometrical data, part attributes, and design knowledge. Hence, this information can be used to generate a 3D solid model and production material information for CAPP as needed. The applicability of the proposed data Structure and the developed system was verified by applying them to the deadweight 300,000 ton of Very Large Crude oil Carrier’s product modeling procedure. The application results showed that the proposed data Structure and the developed system can be efficiently used for overall initial ship design environment.
Jihua Huang - One of the best experts on this subject based on the ideXlab platform.
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Austenite Grain Size Prediction in the Coarse-Grained Heat-Affected Zone of the Developed Cu-Free High-Strength Low-Alloy Hull Structure Steel
Metallurgical and Materials Transactions A, 2020Co-Authors: Xuanwei Lei, Shuanbao Zhou, Jihua HuangAbstract:The developed Cu-free high-strength low-alloy (HSLA) Hull Structure steel has wide potential applications because of its strength, good low-temperature toughness, and satisfactory weldability. As a significant part of microStructure characterization, austenite grain size in the coarse-grained heat-affected zone (CGHAZ) of this steel has not been investigated in any previous study. The present work has developed an equation considering the driving pressure and Zener pinning pressure to predict the austenite grain size in the CGHAZ of this developed Cu-free HSLA Hull Structure steel based on experimental data. In this equation, Zener pinning pressure is taken as a constant because of the high thermal stability of precipitate type I and relatively low thermal stability of precipitate type II in this steel. The results show this equation is applicable under heat input of 7.1 to 71.4 kJ/cm with peak temperature 1623 K to 1673 K (1350 °C to 1400 °C). In both theory and practice, the method for austenite grain size prediction in CGHAZ can be used for other steels that contain precipitates with similar properties.
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phase evolution and mechanical properties of coarse grained heat affected zone of a cu free high strength low alloy Hull Structure steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Shi Dong, Jihua Huang, Jiang Yang, Shuhai Chen, Xingke ZhaoAbstract:Abstract Weldability of a Cu-free high strength low alloy (HSLA) Hull Structure steel is studied. Strengthening contributions of this steel are analyzed and phase continuous cooling transformation in simulated coarse-grained heat affected zone (CGHAZ) is investigated. Indeed, strengthening contributions of simulated CGHAZs under heat input 50 and 20 kJ/cm, respectively, are estimated. It shows this Cu-free HSLA Hull Structure steel is dominated at grain refinement strengthening and supplemented by precipitation strengthening and phase transformation strengthening, while the simulated CGHAZ under heat input 50 or 20 kJ/cm is dominated at phase transformation strengthening and supplemented by solid solution strengthening and grain refinement strengthening. The drawn simulated heat affected zone continuous cooling transformation (SH-CCT) diagram shows this Cu-free HSLA Hull Structure steel can obtain main lath-like microStructures in a wide cooling rate range with low phase start temperature. Mechanical property tests of simulated CGHAZ samples indicate high strengths and good low temperature impact toughness. All results exhibit this Cu-free HSLA Hull Structure steel has satisfactory weldability, which suggests its wide potential applications.
Shi Dong - One of the best experts on this subject based on the ideXlab platform.
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phase evolution and mechanical properties of coarse grained heat affected zone of a cu free high strength low alloy Hull Structure steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Shi Dong, Jihua Huang, Jiang Yang, Shuhai Chen, Xingke ZhaoAbstract:Abstract Weldability of a Cu-free high strength low alloy (HSLA) Hull Structure steel is studied. Strengthening contributions of this steel are analyzed and phase continuous cooling transformation in simulated coarse-grained heat affected zone (CGHAZ) is investigated. Indeed, strengthening contributions of simulated CGHAZs under heat input 50 and 20 kJ/cm, respectively, are estimated. It shows this Cu-free HSLA Hull Structure steel is dominated at grain refinement strengthening and supplemented by precipitation strengthening and phase transformation strengthening, while the simulated CGHAZ under heat input 50 or 20 kJ/cm is dominated at phase transformation strengthening and supplemented by solid solution strengthening and grain refinement strengthening. The drawn simulated heat affected zone continuous cooling transformation (SH-CCT) diagram shows this Cu-free HSLA Hull Structure steel can obtain main lath-like microStructures in a wide cooling rate range with low phase start temperature. Mechanical property tests of simulated CGHAZ samples indicate high strengths and good low temperature impact toughness. All results exhibit this Cu-free HSLA Hull Structure steel has satisfactory weldability, which suggests its wide potential applications.