• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1996년도 특별강연 및 춘계학술발표 개요집
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• pp.163-166
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• 1996

• 국제강구조저널
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• 제18권4호
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• pp.1200-1209
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• 2018

In this study, a probabilistic framework of the damage assessment of pipelines subjected to extreme hazard scenario was developed to mitigate the risk and enhance design reliability. Nonlinear 3D finite element models of T-joint systems were developed based on experimental tests with respect to leakage detection of black iron piping systems, and a damage assessment analysis of the vulnerability of their components according to nominal pipe size, coupling type, and wall thickness under seismic wave propagations was performed. The analysis results showed the 2-inch schedule 40 threaded T-joint system to be more fragile than the others with respect to the nominal pipe sizes. As for the coupling types, the data indicated that the probability of failure of the threaded T-joint coupling was significantly higher than that of the grooved type. Finally, the seismic capacity of the schedule 40 wall thickness was weaker than that of schedule 10 in the 4-inch grooved coupling, due to the difference in the prohibition of energy dissipation. Therefore, this assessment can contribute to the damage detection and financial losses due to failure of the joint piping system in a liquid pipeline, prior to the decision-making.

• 한국융합학회논문지
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• 제6권3호
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• pp.13-18
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• 2015

본 논문은 신축이음으로 배관과 배관사이에 연결되어 압력과 온도를 조절하는 이음의 안전설계에 관한 연구이다. 본 연구의 목적은 외기와 수송유체의 압력으로 인한 팽창과 수축에 의한 파이프 손상의 문제를 해결하고자 하여 파이프에 작용하는 과중한 압력을 감소시키고 사고발생을 예방하고자 하고자 한다. 3가지 유형의 신축이음을 적용하여 각각의 모델의 유동특성을 시뮬레이션 해석을 통하여 관찰한다. 각각의 모델의 형상에 따라 슬리브형, 벨로우즈형, 루프형의 신축이음 특성을 분류한다. 또한 수송 유체가 신축이음을 통과할 때, 배관에서의 열과 압력, 속도의 유동특성을 분석한다. 본 연구의 결과를 이용하면 신축이음 형상에 따른 안전설계에 기여할 수 있을 것으로 판단된다. 또한, 디자인 면에서 융합 기술로의 접목도 가능하여 미적인 감각을 나타낼 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.670-677
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• 2003

Although Gas Tungsten Arc Welding (GTAW or TIG welding) is considered as high quality and precision welding process, it also has demerit of low melting rate. Narrow-gap TIG welding which has narrow joint width reduces the groove volume remarkably, so it could be shorten the welding time and decrease the overall shrinkage in heavy wall pipe welding. Generally Narrow-gap TIG welding is used as orbital welding process, it is important to select the optimum conditions for the automatic control welding This paper looks at the application and metallurgical properties on Narrow-gap TIG welding joint of heavy wall large austenitic stainless steel pipe to determine the deposition efficiency, the resultant shrinkage and fracture toughness. The fracture toughness depends slightly on the welding heat input.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.54-54
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• 2008

• 전산구조공학
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• 제2권3호
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• pp.105-114
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• 1989

파이프 설비는 다양한 두께 및 직경, 길이를 가진 파이프들로 이루어진 구조물로서 정확한 해석을 위해서는 3차원의 유한요소 모델이 필요하다. 그러나 유한요소 모델에 의한 해석방법은 계산시간이 길어질 뿐만 아니라 방대한 양의 컴퓨터 용량을 필요로 한다. 반면에 파이프를 보요소로 가정한 단순한 해석 모델은 파이프 설비의 정확한 거동을 예측하기에 문제점이 많다. 따라서, 본 연구에서는 파이프 설비의 효율적인 해석모델을 제안하고자 한다. 제안된 해석모델은 보요소로 구성된 모델에 접합부 요소만을 추가함으로써 보요소만으로 구성된 모델만큼 단순하며, 또한 파이프 접합부의 국부적인 변형을 고려하기 때문에 파이프 설비의 거동을 정확히 예측할 수 있다. 예제 해석을 통하여 결과들을 비교함으로써 본 연구에서 제안한 모델의 효율성을 입증하였다.

• 한국산학기술학회논문지
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• 제11권1호
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• pp.314-319
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• 2010

본 논문은 초고압 전력케이블의 접속재 개발을 위한 연구결과로써, 접속시스템의 핵심기술인 고절연 고무슬리브의 현장 접속 작업의 용이성을 위한 Carrier Pipe의 구조해석과 주요부의 전기적 특성과 전계의 집중을 완화하기 위한 수치해석 등을 실시하여 구조적 안정성을 평가하려 한다. 절연설계 및 전계완화 해석에 의한 검증과 접속재의 수축거동 해석에 의한 Carrier Pipe의 최적화된 형상으로 두께가 최소 9mm이상을 갖는 Carrier Pipe가 필요하며, 전기적 전계완화 해석결과 고절연 고무슬리브의 중앙매립전극 경계면으로써, 접속재 수축거동 해석 결과와도 일치함을 검증할 수 있었다.

• 한국태양에너지학회 논문집
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• 제36권3호
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• pp.25-31
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• 2016

Gaskets are usually used for the sealing of flange joints. The joint is usually composed of two flanges, a ring gasket and clamping bolts. The metal ring gasket is suitable for pipe flanges, pumps and valve joints in high temperature and high pressure environments. A very high surface stress is developed between a ring type joint gasket and the flange groove when the ring type joint is bolted up in a flange. The dimensions of flanges and ring joint gaskets for the pipe sizes that are in common use are specified in the ANSI codes. However, sometimes it is necessary to make a new design for the flange joint which is not specified in the codes, as the equipment is getting larger and larger in size. This paper presents the contact behavior of Class 600 ring joint gaskets with oval and octagonal cross sections. Five different sizes of gaskets are employed in the analysis, and one of them is newly designed on the basis of analysis results obtained from existing models. Three load steps are used to find the stress, stain and contact pressure etc., and to compare the contact characteristics among the models due to the bolt clamping force and the working surface pressure. ANSYS Workbench version15 is used to conduct the finite element analysis.

• 한국생산제조학회지
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• 제18권6호
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• pp.652-657
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• 2009

MPW(Magnetic Pulse Welding) is a technologies for welding of metals by means of repulsive force on account of the interaction between electro-magnetic field of coil and current induced in outer pipe. These MPW is one of the most useful welding process of welding ability of the dissimilar metal in which cylindrical materials, such as pipe, tube. As the quality of a weld joint is strongly influenced by process parameters during the welding process and the success of the welding to evaluated according to the leakage pressure. Generally, the process parameters is magnetic pressure, the gap between outer pipe and inner pipe, and the ratio of thickness to diameter of pipe(D/T) in MPW. Therefore, the goal of this study was to explain the effect of parameters on the weld joint leakage pressure. For these purposes, FFD(Fractional Factorial Design) were used for the experiment. The measured data were analyzed by regression analysis and verification experiments with random condition were conducted to confirm the suggested experimental model.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.117-122
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• 2022

This paper proposes a method for evaluating the work of manufacturing workers using MediaPipe as a risk factor for musculoskeletal diseases. Recently, musculoskeletal disorders (MSDs) caused by repeated working attitudes in industrial sites have emerged as one of the biggest problems in the industrial health field while increasing public interest. The Korea Occupational Safety and Health Agency presents tools such as NIOSH Lifting Equations (NIOSH), OWAS (Ovako Working-posture Analysis System), Rapid Upper Limb Assessment (RULA), and Rapid Entertainment Assessment (REBA) as ways to quantitatively calculate the risk of musculoskeletal diseases that can occur due to workers' repeated working attitudes. To compensate for these shortcomings, the system proposed in this study obtains the position of the joint by estimating the posture of the worker using the posture estimation learning model of MediaPipe. The position of the joint is calculated using inverse kinetics to obtain an angle and substitute it into the REBA equation to calculate the load level of the working posture. The calculated result was compared to the expert's image-based REBA evaluation result, and if there was a result with a large error, feedback was conducted with the expert again.