• 한국안전학회지
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• 제23권4호
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• pp.19-24
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• 2008

This paper presents and discusses the experimental results on the F10T high strength bolts used in the T-flange joint structure. The experimental works were carried out for the parameters which are flange web thickness, the distance between bolts, prying ratio. The results show that the working stress imposed to bolts decreases as the flange web thickness increases on the other hand the imposed stress to the bolts increases as the distance between two bolts increases. In other words the strength of the T-flange joint increased as the web flange thickness increases and the distance between two bolts decreases. The prying ratio is increased as the distance between two bolts increases and as the flange web thickness decreases However, the degree of stress decrease in flange thickness variation is not that high as the distance variation between two bolts. Finally the equation for predicting the failure stress in T-flange joint structure using F10T high strength bolts was suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.699-704
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• 2002

The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. New the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some deflects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical terming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions fur forming a long-neck flange are simulated by FE analyses with a commercial cede DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion fur forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any deflects.

• 한국정밀공학회지
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• 제19권8호
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• pp.212-219
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• 2002

The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. Now the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some defects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical forming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions for forming a long-neck flange are simulated by FE analyses with a commercial code DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion for forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any defects.

• 소성∙가공
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• 제7권1호
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• pp.36-48
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• 1998

In order to analyze the stretch flange forming characteristics of tailored blanks. laser welded blanks of different thickness and strength combinations were prepared and hole expansion tests were done. The stretch flange formability of laser welded blanks was reduced as increasing the deformation restraining force($strength{\times}thickness$) ratio between two welded sheets. Simulation of stretch forming mode deformation and comparson with experimental results showed that the stretch flange formabili-ty was influenced not only by the difference of the deformation restraining forces between two base sheets but also by the difference of the deformation restraining forces between base sheet and weld. Therefore the stretch flange formability was reduced more rapidly than tensile elongation as increas-ing the deformation restraining force ration. It was also found that simulation of stretch flange forming was more accurate when material properties of weld was given.

• Design & Manufacturing
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• 제14권1호
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• pp.22-29
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• 2020

The analysis was carried out using the press molding analysis program by applying six parameters such as material type change, material thickness, friction coefficient, r_p, r_d and blank holder pressure. As a result of CAE analysis of the soft material DC04 and the relatively hard material HX300LAD, the thickness of the punch R part of the soft material was significantly reduced. The flange portion is greatly increased in thickness in the hard material by the compression action. As a result of considering the deformation amount of 0.6mm, 1.0mm, 1.5mm according to the material thickness, the influence of the thickness is considered to be very small. In case of the material thickness of 0.6mm, the rate of change increases due to the deep drawing depth relative to the material thickness. The sizes of the punches R and die R have the greatest influence on the change in thickness of the material in drawing molding, the smaller the punch R, the thinner the edges of the product, The larger the R of the die, the greater the material thickness of the flange portion. As the coefficient of friction and the blank holder pressure increase, the frictional force of the flange portion increases, which increases the radial force in the drawing process and increases the thickness change of the flange portion.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.123-127
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• 1996

The tendency of wrinkling formation on the flange of a deep-drawn rectangular container was investigated experimentally under different process conditions. Such process variables as blank size, sheet thickness, blank-holding force, and depth of drawing are chosen to examine their effects on the flange wrinkles of the products. Number and amplitudes of the wrinkles are measured along the periphery of the flange and compared between each case of process condition.

• 한국산학기술학회논문지
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• 제8권5호
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• pp.1179-1185
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• 2007

본 논문은 슬래브내의 보 상부철근의 영향을 파악하기 위한 해석적 연구로 슬래브가 있는 보-기둥 접합부에서 기존의 설계방법인 직사각형 단면 내에 상부철근을 2단으로 배근한 보와 동일량의 상부철근을 직사각형 단면에 1단만 배근하고 나머지는 보의 적정 플랜지폭 내에 분산 배치하여 상부철근의 배치에 따라 보의 휨 강도가 어떻게 변화하는지를 정량적으로 평가할 수 있도록 하는 것이다. 이러한 연구 목적을 수행하기 위하여 상용화된 범용 구조해석 프로그램인 ANSYS를 이용하여 모델링하고, 비선형 구조해석을 실시하였다. 플랜지폭, 플랜지(슬래브)두께 및 상부 플랜지내에서의 철근의 위치 등을 변수로 한 수치해석을 통하여 보의 최대내력을 비교 검토한 결과, 플랜지폭의 영향은 상부 인장철근을 1단으로 직사각형 단면에서 멀리 배치할수록 내력차이가 증가하는 것을 확인하였으며, 플랜지폭이 동일한 계열에서 내력이 증가되는 비율은 플랜지두께의 영향을 크게 받지 않는 것으로 나타났고, 상부 인장철근의 위치에 따른 내력은 슬래브두께가 증가할수록 내력의 차이가 줄어드는 것으로 나타났다.

• 한국안전학회지
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• 제38권4호
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• pp.1-7
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• 2023

The steel wheels of urban railway vehicles gather a lot of data through regular measurements during maintenance. However, limited research has been carried out utilizing this data, resulting in difficulties predicting the maintenance period. This paper studied a machine learning model suitable for mileage prediction by studying the characteristics of mileage change according to diameter and flange thickness changes. The results of this study indicate that the larger the diameter, the longer the travel distance, and the longest flange thickness is at 30 mm, which gradually shortened at other times. As a result of research on the machine learning prediction model, it was confirmed that the random forest model is the optimal model with a high coefficient of determination and a low root mean square error.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.49-52
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• 2008

The design strength of panel zones, which was based on Krawinkler model, was investigated by comparing it with existing test and FEM results. The design strength overestimates of the strength of panel zones with thick column flange while it matches well with the strength of panel zones with thin column flange. More extensive studies are needed to develop a mathematical model which can properly define the inelastic behavior of panel zones with various column flange thicknesses and to determine a more rational design strength.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.177-180
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• 2009

Tube hydroforming provides a number of advantages over the conventional stamping process, including fewer secondary operations, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength and stiffness. A hydroformed vehicle body component has an attachment flange or the like-formed as an integral part of the hydroforming process. For a given flange shape, a parting plane for the dies is established relative to which the various surfaces of the flange shape, in cross section, have no significant reverse curvature. This study shows analysis results that form the flanged tubular parts in the hydroforming. The thickness variations and defects during the hydroforming for flange forming could be analyzed by FE analysis. FE analysis was performed by LS-DYNA/Dynaform 5.5.