• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2001년도 춘계학술발표대회 개요집
• /
• pp.232-234
• /
• 2001

• 한국기계가공학회지
• /
• 제19권4호
• /
• pp.79-84
• /
• 2020

Induction bending via high-frequency heating is widely used for manufacturing pipe and section steel bends. It allows productivity improvement, unit cost reduction, delivery time compliance, and good mechanical properties. The recent increase in high-end vessels and offshore plants has raised the demand for high-frequency bending, which should improve the product quality and reduce the costs by simplifying the fabrication process; therefore, the characteristics and performance of this technique must be studied and proper design technology is required. During hot pipe bending via induction heating, the outward wall thickness of the pipe is thinned due to tensile stress and this thickness reduction cannot exceed 12.5%. This study focused on pipe bends with a bending curvature of 5D and their optimization design; in particular, the conditions that can both improve the productivity of the high-frequency bending process and keep the maximum thickness reduction below 12.5% were determined.

• 한국기계가공학회지
• /
• 제21권8호
• /
• pp.72-78
• /
• 2022

Bending using high-frequency induction heating is used to bend pipes and sections, and is currently widely applied in industrial fields such as power generation facilities, ships, onshore plants, and offshore plants. The purpose of this study is to study the manufacturing process and design technology of high-frequency bending of pipe to make the best pipe design arrangement. Although various studies are being conducted in the field of high-frequency bending, more research is needed on high-frequency bending of pipes for ship building and offshore plants. The purpose of this study is to review the feasibility of production design using 3D model tool of S3D and AM(PDMS), and to review and improve bending thickness reduction, reduction rate, and roundness.

• 마이크로전자및패키징학회지
• /
• 제31권3호
• /
• pp.42-49
• /
• 2024

전자기파 차폐 소재의 시장에서는 고주파 대역에서의 뛰어난 차폐 성능과 함께 유연성과 내구성이 중요한 요구사항으로 부각되고 있다. 특히 전자기파 간섭 문제를 해결하기 위해 고성능 EMI 필름의 필요성이 커지고 있으며, 이는 스마트 전자기기, 자동차 전장 시스템, 통신 장비 등 다양한 산업 분야에서 더욱 중요해지고 있다. 본 연구에서는 트라이모달 실버 페이스트를 개발하고 EMI 필름으로 제작하여 그 성능을 평가하였다. 개발된 실버 페이스트는 변성 에폭시 바인더를 사용하여 스크린 인쇄 공정에 적합한 물성을 갖추었으며, 5G 영역의 고주파 대역(26.5 GHz ~ 40 GHz)에서 차폐 성능이 평균 -99 dB로 우수함을 확인하였다. 특히 33.6 GHz에서 -90.3 dB의 차폐 효과를 보였다. 유연성 및 내구성 테스트 결과, 곡률반경 1 mm에서도 필름의 유연성을 유지하며 벤딩 사이클 시험에서 outer 벤딩의 경우 초기 저항이 0.51 Ω에서 10,000 사이클 후 0.64 Ω로 약 25.5% 증가하였고, inner 벤딩에서는 약 3.6% 감소하여 압축 응력에 대한 저항 감소를 확인하였다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2008년도 춘계학술대회 논문집
• /
• pp.399-400
• /
• 2008

• 한국정밀공학회지
• /
• 제18권9호
• /
• pp.110-121
• /
• 2001

During hot pipe bending using induction heating, the wall of bending outside is thinned by tensile stress. In design requirement, the reduction of wall thickness is not allowed to exceed 12.5%. So in this study, two methods of bending, one is loading of reverse moment and the other is loading of temperature gradient, have been investigated to design pipe bending process that satisfy design requirements. For this purpose, finite element analysis with a bending radius 2Do(outer diameter of pipe) has been performed to calculate proper reverse moment and temperature gradient to be applied. Induction heating process has been analyzed to estimate influence of heating process parameters on heating characteristic by finite difference method. Then pipe bending experiments have been performed for verification of finite element and finite difference analysis results. Experimental results are in good agreement with the results of simulations.

• 한국기계가공학회지
• /
• 제14권4호
• /
• pp.21-27
• /
• 2015

Induction bending is a method that allows the bending of any material that conducts electricity. This technology applies a bending force to a material that has been locally heated by an eddy current induced by a fluctuating electromagnetic field. Induction bending uses an inductor to locally heat steel through induction. This results in a narrow heat band in the shape to be bent. In general, the reduction of thickness attenuation of a large-diameter steel pipe is not allowed to exceed 12.5%. In this paper, in order to meet the standard of thickness attenuation reduction, a non-uniform heating temperature jump-bending process was investigated. As a result, the developed bending technique meets the requirements of thickness attenuation reduction for large-diameter steel pipes.

• 소성∙가공
• /
• 제19권2호
• /
• pp.79-87
• /
• 2010

The Pipe bending process using high frequency local induction heating is an advanced technique to bend pipes with a small bending radius and a large diameter. Even though the pipe bending process is a quite widespread engineering practice, it depends heavily upon trial and error method by field engineers with several years of experience. So it is necessary to develop an integrated methodology for optimum design of the pipe bending process. During hot pipe bending using induction heating, outward wall thickness of a pipe is thinned due to tensile stress and the reduction of wall thickness is not allowed to exceed 12.5%. Taguchi method and dynamic reverse moment is proposed to maintain a reduction ratio of thickness within 12.5%, when D/t ratio is high. An application of the proposed approach was compared with those of the finite element analysis and has good in agreements.

• 센서학회지
• /
• 제9권1호
• /
• pp.22-27
• /
• 2000

고자왜특성과 연자성특성을 가짐으로서 우수한 자기기계결합특성을 나타내는 아몰퍼스 FeCoSiB 박막의 스트레인 검출특성에 대해 연구하였다. 투자율은 박막기판을 마이크로메타를 이용하여 벤딩시켜 박막에 스트레인을 인가하면서 조사하였으며, 이때 박막에 스트레인이 인가되면 박막의 자기기계결합에 의해 투자율이 변화하였다. 스트레인에 의한 성능지수 $F=({\Delta}{\mu}/{\mu})/{\varepsilon}$ (단위스트레인에 대한 투자율의 변화)가 $1.2{\times}10^5$라는 매우 높은 값을 나타내어 본 연구에서 제작한 박막이 스트레인에 대하여 고감도특성을 가지고 있음을 알 수 있었다. 또한 제작된 박막을 센서소자로 응용하기 위해 박막을 미세 가공하고, 스트레인에 대한 고주파 임피던스의 변화를 조사하였으며, 박막의 우수한 자기기계결합특성으로 박막패턴의 임피던스는 인가된 스트레인에 의해 민감하게 변화되었다. 특히, 100MHz의 구동주파수에 있어서 $300{\times}10^{-6}$의 스트레인이 인가된 경우 46%의 임피던스변화율이 얻어졌다. 따라서 본 연구에서 제작한 박막소자는 초고감도의 스트레인 센서로 사용될 수 있을 것으로 기대된다.