• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.344-349
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• 2003

The purpose of this study is to ascertain the ability of New type cutter using Hybrid Rocket Propulsion System to cut normal carbon steel and also compound metal like stainless steel which cannot be cut by regular oxygen-acetylene cutter. To compare cutting performance, Two different types of experiment with oxygen-acetylene and Hybrid Combustion cutters were performed. As a result, Hybrid Combustion cutter is used to cut both carbon steel and stainless steel with cutting speed of 400mm/min(carbon steel) and 250mm/min(stainless steel). Otherwise, oxygen-acetylene cutter can be used to cut only carbon steel with cutting speed of 500 $^{\sim}$ 700mm/min. The possibility of Hybrid Combustion cutter as a cutting machine was confirmed.

• Corrosion Science and Technology
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• 제16권2호
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• pp.85-89
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• 2017

One of the most challenging issues in the oil and gas industry is corrosion assessment and management in subsea structures or equipment. At present, almost all steel pipelines are sensitive to corrosion in harsh working environments, particularly in salty water and sulphur ingress media. Nowadays, the most commonly practiced solution for a damaged steel pipe is to entirely remove the pipe, to remove only a localized damaged section and then replace it with a new one, or to cover it with a steel patch through welding, respectively. Numerous literatures have shown that fiber-reinforced polymer-based composites can be effectively used for steel pipe repairs. Considerable research has also been carried out on the repair of corroded and gouged pipes incorporated with hybrid natural fiber-reinforced composite wraps. Currently, further research in the field should focus on enhanced use of the lesser and highly explored hybrid-biocomposite material for the development in corrosion prevention. A hybrid-biocomposite material from renewable resource based derivatives is cost-effective, abundantly available, biodegradable, and an environmentally benign alternative for corrosion prevention. The aim of this article is to provide a comprehensive review and to bridge the gap by developing a new hybrid-biocomposite with superhydrophobic surfaces.

• Journal of Welding and Joining
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• 제33권2호
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• pp.69-77
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• 2015

High strength steels have been continually being developed to improve in fuel economy in automotive and ensure safety of passengers. New bonding and welding methods have been required for improving weldability on high strength steels. In this study, resistance spot welding and Weld-bond with nugget diameters of 4.0mm, 5.0mm, 6.0mm and 7.0mm were produced and tested, respectively. In order to confirm the effect of nugget diameters on tensile shear characteristic of the Weld-bond, tensile shear characteristics of Weld-bond were compared with those of resistance spot welding and adhesive bonding. Peak load of Weld-bond were increased as the nugget diameter increases. After appearing maximum peak load continuous fracture followed with second peak owing to load being carried by resistance spot weldment. Fracture modes of the adhesive layer in Weld-bond fractures were represented by mixed fracture mode, which are cohesive failure on adhesive part and button failure at resistance spot welds. The results showed that the tensile shear properties can be improved by applying Weld-bond on TRIP steel, and more apparent with nugget diameter higher than 5${\surd}$t.

• Journal of Welding and Joining
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• 제34권6호
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• pp.28-34
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• 2016

Galvannealed(GA) steels are now generally used in car body manufacturing for corrosion resistance. In this study, the weldability and joint mechanical behavior of a newly developed 1.2GPa grade GA ultra high strength TRIP(transformation induced plasticity) steel was investigated for three joining processes, such as adhesive bonding, resistance spot welding and weldbonding. Under both shear and peel stress conditions, the failure mode of the adhesive joints were the mixture of the adhesive cohesive failure, adhesive interface failure and coating layer failure. It means that the adhesion strength of GA coating onto the base metal was similar to that of adhesive bonding onto the GA coating. Under the shear stress condition, the weldbonding exerted to expand the optimal spot welding condition of 1.2GPa GA TRIP steel because the strength of adhesive bond overwhelmed that of the resistance spot weld. Under the peel stress condition, the weldbonding also exerted to expand the optimal spot welding condition of 1.2GPa GA TRIP steel by inducing the tear fracture mode rather than the partial plug fracture mode.

• 한국주조공학회지
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• 제32권2호
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• pp.109-113
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• 2012

• Journal of Advanced Marine Engineering and Technology
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• 제28권5호
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• pp.691-698
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• 2004

레이저빔과 아크를 하나의 용접 프로세스로 병합하는 기술에 관해서는 이미 70년대부터 알려져 왔으나 별다른 개발로 이어지지 못하다가 최근에서야 다시 눈을 돌리게 되었다. 이 기술의 핵심과제는 아크의 장점과 레이저의 장점을 어떻게 단일 혼합 프로세스로 조합하느냐 하는 것이다. 과거 레이저빔을 처음 사용할 때 만해도 산업용으로서 적합성을 증명해야 했으나 지금은 이미 자동차 산업에서 재래기술로 치부되고 있다.(중략)

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2005년도 춘계학술발표대회 논문집
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• pp.48-52
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• 2005

• 한국기계가공학회지
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• 제20권12호
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• pp.24-29
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• 2021

Recently, owing to the high demand for eco-friendly cars in the automotive industry, noise and vibrations have become major challenges. The use of laminated damping steel is increasing in response to these demands. Laminated damping steel is primarily used in sound insulation plates. The vibration energy is converted into thermal energy due to the viscoelastic resin being located between two steel sheets and being able to damp the vibrations when an external force, such as, noise or vibration is applied to the steel plate. Laminated damping steel is chiefly applied to dash panels in automotive body parts, and because of its structure, junction technology for bonding with other components is necessary. However, there has not been sufficient research conducted on junctions. In this study, regardless of the electrode shape, in the range of 4.0 ~ 8.0 kA welding current, the same welding force and welding time were applied which were 2.8 kN and 200 m/s (12 cycles) and the tensile shear load and nugget size were analyzed after the resistance spot welding between different materials of laminated damping steel with a thickness of 1.035 mm. The results show that in the range of 5 ~ 8 kA welding current, 1.035 mm laminated damping steel meets the MS181-15 standard, which is the technical standard of Hyundai-Kia Motors.

• Journal of Welding and Joining
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• 제23권6호
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• pp.67-71
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• 2005

This paper is concerned with a study on fracture strength of composites in an adhesive single lap joint. The tests were carried out on joint specimens made with hybrid stacked composites consisting of the polyester and bamboo natural fiber layer. The main objective of this work was to evaluate the fracture properties adjacent to adhesive bonded joint of natural fiber reinforced composite specimens. From the results, natural fiber reinforced composites have lower tensile strength than the original polyester. But tensile-shear strength of natural fiber reinforced composites with bamboo layer far from adhesive bond is as high as that of the original polyester adhesive bonded joints. Spew filet at the end of the overlap reduced the stress concentration at the bonded area. Spew fillet and position of bamboo natural fiber layer have a peat effect on the tensile-shear strength of natural fiber reinforced composites including adhesive bonded joints.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 춘계종합학술대회
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• pp.425-431
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• 1999

본 연구에서는 플라즈마 감시에 의한 용접성 평가방식을 채택한다. 플라즈마에서 발생하는 자외선신호를 반도체 광센서를 사용하여 검출하고, 감시장치로 쓰이는 개인용 컴퓨터에 고속으로 전달, 저장하는 장치를 개발한다. 이 장치를 사용하여 용접 데이터베이스를 구축하고, 용접성과 플라즈마 신호와의 관계를 평가하고, 분석할 것이다. 이 분야에 대한 연구동향을 하면 표2와 같다. 그러나 이 연구들은 모두 사용한 장치의 특성, 플라즈마발생원에 대한 센서의 상대적 위치 및 자세와 획득 신호와의 관계, 용접할 때 발생하는 열의 센서에 대한 영향, 잡음이 취득된 신호에 미치는 영향 및 회피방법 둥에 대한 언급이 없다. 따라서 논문에 실린 신호의 파형은 대부분 일관성이 없으며, 참고가 어렵다. 본 연구에서는 이러한 관계를 도출하고, 특히 잡음의 영향을 최소화하는 장치화에 주안점을 둔다.