Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Analysis of Spot And Line Heating Method For Correcting Thin Plate Deformation
Park, Jung Goo (Institute of Industrial Technology, Samsung Heavy Industries Co., LTD.) | Jang, Kyoung Bok (Institute of Industrial Technology, Samsung Heavy Industries Co., LTD.) | Cho, Si Hoon (Institute of Industrial Technology, Samsung Heavy Industries Co., LTD.) | Jang, Tae Won (Institute of Industrial Technology, Samsung Heavy Industries Co., LTD.)
ABSTRACT During fabrication of deck house block in passenger ships, the problem of unexpected large deformation and distortion frequently occurs. Hence, amending of these deformation become more important in thin plate welding. The spot heating and line heating methods were very widely employed to amend deformation of thin plate structures. Few papers are available on the working conditions of spot heating method but only little information on deformation control. In this study, evaluation was carried out on the temperature distribution of spot and line heating methods using FEA and practical experiments for various heating time. In FEA, heat input model was established using Tsuji's double Gaussian heat input mode (Tsuji, I., 1988). This model was verified by comparing with experimental data. Also radial shrinkage and angular distortion due to spot heating were determined and compared with experimental results. Thermo elasto-plastic analysis was performed using commercial FE code, MSC/MARC. Radial shrinkage and angular distortion were measured using 3D measuring apparatus. Based on these results, criteria for amending thin plate fairing was established in our fabrication yard. INTRODUCTION In recent years of ship building technology, thin plate welding and control of its deformation is considered as a serious problem. During the fabrication of thin plate structures, welding distortions are inevitable and serious problem of whole ship structure in strength. Because of the need to reduce total weight of ships, deck plate thickness has been gradually reduced resulting in use of 5mm thickness plate associated with buckling distortion during deck block fabrication. The best way to control buckling distortion is to optimize welding parameters and structural parameters. But this requires lot of trial and error experiments. In many cases, line heating or triangular heating is not in much correct to control thin plate deformation.
- Transportation > Passenger (0.55)
- Transportation > Marine (0.49)
Prediction Method For Welding Deformation of Curved Block By Equivalent Loading Method
Jang, Kyoung Bok (Institute of Industrial Technology, Samsung Heavy Industries Co., LTD.) | Park, Jung Goo (Institute of Industrial Technology, Samsung Heavy Industries Co., LTD.) | Cho, Si Hoon (Institute of Industrial Technology, Samsung Heavy Industries Co., LTD.) | Jang, Tae Won (Institute of Industrial Technology, Samsung Heavy Industries Co., LTD.)
ABSTRACT In order to achieve high productivity of assembly hull blocks, it is important to predict welding deformations accurately and to apply these data to the production planning. In the deformation analysis of hull block, simplified methods (elastic analysis) such as inherent strain method(Nomoto, T., 1972), equivalent loading method(Dean, D., 2002) and local & global approach (Jang, K., 2003)are usually used instead of thermal-elastic-plastic analysis (Fujita, Y., 1997) because of calculating time and cost. To be much more practical, these simplified methods should consider gravity effect of plate and contact condition between the plate and the positioning jig.In this research, using finite element method, practical predicting method for the welding deformation of the curved hull block with considering welding sequence, gravity effect and contact condition is proposed. Contact condition between the plate and the positioning jig is considered by judging reaction forces at positioning jig of calculation step. INTRODUCTION To achieve high productivity of assembly blocks of hull structures, it is important to predict welding deformation accurately and to apply these data to the production planning. For this purpose the transient thermal-elastic-plastic analysis may be utilized. However, this method is not a practical approach to analyze the deformation of large and complex structures, such as curved hull block of ship, in view of calculation time and cost. In the deformation analysis of hull block, therefore, elastic analysis such as inherent strain method (Takeda, Y., 2002), equivalent loading method and local & global approach are usually used. Past research activities of these simplified methods have been focused on the prediction of welding deformation of small size specimen and simple flat block, in other words, there have been very few treating the welding deformation of large and curved block (Luo, Y., 1996, Michleris, Y., 1997).