http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
고주파 유도가열을 이용한 오목 곡면 곡가공에 관한 연구
현충민,김대경,문승환,박정서,도규원 대한조선학회 2019 大韓造船學會 論文集 Vol.56 No.2
In shipbuilding, accurate fabrication of curved hull plates is one of the most important steps, since the shape of ship hull, which is very critical in the overall performance of a ship, is a collection of such plates. The curved hull plates forming process requires a significant amount of time by skilled workers in shipbuilding. In general, the workers cause thermal distortion in the plate and forming initial shape using gas heat source. So shipbuilding companies need skilled workers who have long experience. To solve the problem, a lot of researchers tried to develop automation system for curved hull plates. In this paper, we propose automatic heating system with gantry robot, high frequency induction heater to replace the gas heat source and automatic measurement system. We apply the system to forming concave type plate that is actually used in ship manufacturing. In addition, a system was developed to automatically generate heating information, such as the heating location and the heating speed, for actual heating process. Then the system was applied to the actual heating material. It is shown that the proposed triangle heating pattern makes desired concave shape successfully. The induction heating system showed that it can be used for automation system of curved hull plates forming process replacing gas heat source.
현충민,이명수,조시훈,장태원,Hyun, Chung Min,Yi, Myung Su,Cho, Si Hoon,Jang, Tae Won 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.1
Due to of high intensity, lower noise and easy controllability of the heat, induction heating system became well known. Induction heating method has been suggested as substitute for the gas heat source and adopted in the automation of curved hull forming system. In this study, an investigation was accomplished to find the effects on the change of material properties when the induction heating was applied on the mild steel plate. Plates were heated using weaving method to get sufficiently heat affected zone and then cooled with water or in the air. The mechanical properties of the heated plate were evaluated. As results, the tensile test, impact test and microstructures satisfied the class rule.
고유 변형도법과 리메슁 기술을 접목한 블록의 역세팅 형상 예측기술
현충민(Chung-Min Hyun),최한석(Han-Suk Choi),박창우(Chang-Woo Park),김성훈(Sung-Hoon Kim) 한국해양공학회 2017 韓國海洋工學會誌 Vol.31 No.6
In order to reduce the cost of corrections and time needed for the block assembly process, the reverse setting method is applied for a back-heated block to neutralize deck deformation. The proper reverse setting shape for a back-heated block to correct deformation improved the deck flatness, but an excessive amount of reverse setting could inversely affect the flatness of the block. A prediction method was developed for the proper reverse setting shape using a back-heated block, considering the complex geometry of blocks, thickness of the deck plate, and thermal loading conditions such as welding and back-heating. The prediction method was developed by combining the re-meshing technique and inherent strain-based deformation analysis using the finite element method. Because the flatness deviation was decreased until the lower critical point and thereafter it tended to increase again, the optimum value for which the flatness was the best case was selected by repeatedly calculating the predefined reverse setting values. Based on this analysis and the study of the back-heating deformation of large assembly blocks, including the reverse setting shape, the mechanism for selecting the optimum reverse setting value was identified. The developed method was applied to the actual blocks of a ship, and it was confirmed that the flatness of the block was improved. It is concluded that the developed prediction method can be used to predict the optimum reverse setting shape value of a ship’s block, which will reduce the cost of corrections in the construction stage.
박정서,문승환,현충민,강병권,김경수,고광희 (사)한국CDE학회 2015 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2015 No.동계
Geometric similarity evaluation is necessary to find the difference between the designed and fabricated shapes, and to determine if the desired shape has been obtained. This evaluation is an essential process for automation of curved hull forming. An existing algorithm for similarity evaluation consists of four steps: 1.Localize the designed shape against the measured one. 2. Compute the Euclidean distances between the two shapes. 3. Count the number of points whose distances are less than the user defined tolerance. 4. Calculate the ratio of the number of points in Step 3 to the total number of points. Although this approach can be used for the automatic thermal forming process, it cannot reflect the inherent characteristic features that are generated in the process of heating information calculation for thermal forming, resulting in similarity values that do not correctly reflect the current state of the plate under forming. In order to solve this problem, a new geometric similarity evaluation method is proposed. The method considers the properties of heating information and the thermal forming process. The new method is based on the geometric shape difference in terms of Euclidean distance measure, the differential properties and heating information at each iteration, all of which are combined to provide quantitative values for similarity. It was demonstrated in the automatic thermal forming system with various real examples.