Papers by Keyword: Shipbuilding

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Authors: Xiao Jun Zhu, Fu Yu Yan, Peng Wang, Zhi Jie Zhu
Abstract: The radial flexibility of ship pressure hull directly effects the structure tension of pressure hull, so it must be measured and controlled. At present, stay bar method is mainly used to measure it in shipyards and the method has low precision and efficiency, many artificial errors. Electronic total stations (ETS) are the main equipments of precision control now and they have high precision, but are seldom used in shipbuilding. So the paper presented a new method to measure the radial flexibility of ship pressure hull with ETS and transfer station measurement method. The data measured in different stations could be transformed and dealt with. Then the plane and the projection point on the plane could be calculated in the same coordinate system. Finally the radial flexibility of ship pressure hull could be worked out according to the theory of least squares. The new method is very easy to operate and have high efficiency. Experiments showed that the method has high precision.
Authors: Ming Di Zong, Hou Fang Sun
Abstract: Shipyards are facing challenges when trying to manage their project plan under make to order mode and, at the same time, control their production process in a pull way according to the lean manufacturing principle. A Lean shipbuilding planning and pull-way control integrated system (LSPCIS) model is established, which provides the architecture of realizing the lean principle in planning and production control area for shipbuilding. Then, a Project Plan Restricted Pull-way production control method (PPRP) is introduced where the bottom level is based on pull principle, while under the restriction of receding horizon plan and project plan. The study reveals that even under the make to order production mode of shipbuilding, it is still possible to establish a leanness oriented planning and production Control system, where the receding horizon plan can work as a middle level between the project plan and pull-way production control. The result of a production process simulation is introduced at the end of the paper, to validate the advantage of the PPRP control method comparing with the normal KANBAN control and pure push way of material delivery.
Authors: Kamran Shafiee, Zeng Xi Pan, Stephen van Duin, Nathan Larkin
Abstract: In this paper we developed a novel and cost effective automated system for use in the Australian shipbuilding industry. We began by investigating current shipbuilding processes and determining the most feasible area where automation could be further developed. Then we designed an automation concept with the objective of developing a highly flexible system. A prototype of the integrated tool was developed for preliminary testing in a simulated industry assembly process, the results of which were benchmarked against a manually fabricated assembly. The outcomes from the benchmarking showed the feasibility of such a system and allowed us to determine the future direction for further development of the integrated tool.
Authors: Krzysztof Dudzik, Adam Charchalis
Abstract: The results of corrosion properties research of aluminum alloy AW 7020 (AlZn5Mg1) welded by friction stir welding FSW were presented. Friction Stir Welding (FSW) a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. In the article the parameters for friction stir welding of sheets made of AlZn5Mg1 (7020) alloy was presented. The study was carried out in accordance with the requirements of the ASTM G 106. EIS measurement was performed in three electrode system in an artificial seawater (3.5% NaCl). Impedance studies were carried out at the corrosion potential. Changed voltage signal amplitude in the range ± 10 mV and frequency range of changes was as follows: 100 kHz - 0.1 Hz. Atlas 0531 EU & IA potentiostat was used for studies. The results of electrochemical impedance spectroscopy are presented in the form of parameters characterizing the corrosion process. Obtained results were statistically analyzed. The electrochemical impedance spectroscopy studies have shown that the joint welded by FSW has better electrochemical corrosion resistance than the native material - AW-7020 alloy. Original value are received results of the corrosion properties of new method friction stir welded AlZn5Mg1 alloy compared with the native material.
Authors: Guillaume Rückert, Myriam Chargy, François Cortial, François Jorez
Abstract: FSW process has been evaluated on three shipbuilding steels (DH36, S690QL and 80HLES steels) by fully penetrated butt welds on 8mm thick plates. Non destructive tests were carried out to highlight the presence of intrinsic defects known for the welding process (eg kissing bond). The validated inspection methodology (volume and surface testing) confirm the integrity of welds and the absence of geometrical defects for examinations and mechanical tests as part of a qualification procedure.
Authors: Zhong Chi Liu, Bo Zhou, Soon Keat Tan
Abstract: The lifting padeyes are widely used in the offshore and shipbuilding industry. The design of lifting padeye requires extremely high safe reliability and economic rationality. Based on finite element analysis (FEA), the variations of stress and deformation with external force and hoist angle are analyzed. For minimizing cost of steel, optimum design models of lifting padeye were built and the reliability of the optimum design scheme was proved. The results show that the optimum design accords with structure design principle and the cost of padeye steel reduce notably.
Authors: Joon Sik Park, B.Y. Jung, Hiroshi Yajima, Jong Bong Lee
Abstract: In this study, the effect of thickness on the fracture toughness of the steel plate with the thickness of 80mm has been investigated by the wide plate tensile test and ESSO test. The fracture toughness for crack initiation and propagation was evaluated quantitatively for the full thickness specimen. It was found that EH-36 grade steel with the thickness of 80mmt showed the KIC value of 164kgf/mm1.5 at -145°C. Also, large-scale ESSO test result showed that the steel with the thickness of 80mm had 520kgf/mm1.5 at -10°C. Although it was known that the fracture toughness decreases with the increase of the plate thickness, EH-36 grade steel with the thickness of 80mm had enough values of fracture toughness to prevent the crack initiation and arrest the brittle crack propagation.
Authors: Krzysztof Dudzik, Adam Charchalis
Abstract: The article presents the research results of hardness values distribution of friction stir welded joint (FSW) alloy AW 7020 (AlZn5Mg1). FSW is a method of welding in the solid state, mechanical properties of joints welded by that method can be higher than that for arc welding techniques (MIG, TIG). The parameters of friction stir welding (FSW) used to join 7020 alloy were presented. Metallographic analysis showed the correctly structured FSW welded 7020 alloy. The study was carried out using Vickers hardness HV5 in accordance with the requirements of the Polish Standard PN-EN 6507 using a hardness testing machine HPO-10. The location of measurement points in the butt joint was determined in accordance with PN-EN 1043-1:2000. The indenter load was 49 N. In order to determine the effect of bonding method on structure change of the material microscopic examination was performed using an optical microscope ZEISS Axiovert 25.The test specimens were polished and then etched with KELLER reagent. This enabled the precise identification of zones present in the joint, such as: weld nugget, thermo-mechanically affected zone, native material. To determine the grain size in the different zones of joints bonded by FSW AxioVision 4.8.2 software was used. Hardness testing in across researched joints showed that the highest value of hardness is in the weld and the lowest is in the native material.
Authors: Krzysztof Dudzik, Mirosław Czechowski
Abstract: The paper presents the research results on the mechanical properties of aluminum alloy 7020 and its FSW and MIG welded joints. For comparison, alloy 5083 – the most currently used in shipbuilding alloy was chosen as well as 5059 – the new high-strength alloy. Besides, the native material alloys there were investigated their joints welded by FSW and MIG – the same methods as alloy 7020. Welding parameters used for the connection of the sheets made of 7020, 5083 and 5059 alloys were presented. Metallographic analysis showed the correct construction of structural bonded joints.Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. FSW method can be an alternative to traditional arc welding methods, especially MIG, which is the most common method of joining aluminum alloys used in shipbuilding. The research was carried out using a static tensile test in accordance with the requirements of the Polish Standards PN-EN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of +20 oC.Friction stir welded joints of tested alloys have higher strength properties as compared to MIG welded joints. The 7020 alloy has higher strength properties then alloys 5083 and 5059. The yield stress is higher by 14.8% as compared to alloy 5083, and by 11.7% as compared to the alloy 5059. Plastic properties of alloy 7020 are the lowest, but with reserves meet the requirements of classification societies. The joints welded by FSW of alloy 7020 have the highest strength properties of all researched joints – higher then alloys 5083 and 5059 joints welded by FSW and joints of all alloys welded by MIG.
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