• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2005년도 추계학술발표회 및 workshop
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• pp.125-125
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• 2005

• 한국표면공학회지
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• 제51권2호
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• pp.133-137
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• 2018

Plasma devices such as jets, pencils, and torches have been developed as new tools that help penetration of target agents and applied to plasma medicine. However, these devices cannot be used in a large area. Therefore, we introduced a flexible plasma device, which can be treated of large area and designed as bendable plasma. In additional, in vitro model based on agarose gel was prepared that can be show effectiveness in the depth of penetration. Plasma treatment conditions such as power, time and distance can be optimized on the agarose gel wound model. The chemical structure of changed polysaccharides was predicted due to reactive excited atoms and molecules, UV photons, charged particles and reactive oxygen and nitrogen species (RONS).

• 한국기계가공학회지
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• 제12권6호
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• pp.30-36
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• 2013

An FFD(flexible fine die) is an embossed mold that consists of a thin plate ranging from 0.6 to 3 mm in thickness. FFDs are primarily used for cutting LCD films and F-PCB sheets. In the high-speed micro-milling process of flexible fine dies, the lubrication and cooling of the cutting edges is very important from the aspect of eco machining and cutting performance. In this paper, a comparative study of tool wear and surface roughness between cutting fluid and hybrid lubrication for eco-machining of FFD was conducted for processes of high-speed machining of highly hardened material (STC5, HRC52). Especially, the incorporated fluid method for eco machining, in which the cutting performances can be simultaneously measured, was introduced. The machining results show that hybrid lubrication, instead of conventional cutting fluid, leads to excellent tool wear and surface roughness and represents the proper conditions for eco micro-machining of flexible fine dies.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.522-527
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• 2013

In this study, dynamic response control of a flexible wing such as gust loads alleviation using sliding mode control method is presented. To achieve this purpose, trailing edge control surface of a flexible wing is used as control means generating the aerodynamic control force. Aeroservoelastic CASE) model consisting of aeroelastic plant, control surface actuator model, and gust model depicting the atmospheric turbulence is formulated in the state space. A sliding mode controller based on the estimated state vector is designed for active dynamic response control of flexible wing aeroservoelastic model. The performance of the controller designed is demonstrated via numerical simulation for the representative flexible wing model under atmospheric turbulence loading.

• 소성∙가공
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• 제18권7호
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• pp.556-564
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• 2009

Flexible forming process for sheet material using reconfigurable die is introduced based on numerical simulation. In general, this flexible forming process using the reconfigurable die has been utilized for manufacturing of curved thick plates used for hull structures, architectural structures and so on. In this study, numerical simulation of sheet metal forming process is carried out by using flexible dies model instead of conventional matched die set. The numerical simulation and experimental verification for sheet metal forming process using a flexible forming machine that is more suitable for thick plate forming process are carried out to confirm the appropriateness of the simulation process. As an elastic cushion, urethane pads are utilized using hyperelastic material model in the simulation for smoothing the forming surface which is discrete due to characteristics of the flexile die. In the flexible forming process for sheet metal, effect of a blank holder is also investigated according to blank holding methods. Formability in view of occurrence of dimples is compared with regard to the various punch sizes. Consequently, it is confirmed that the flexible forming for sheet material using urethane pad has enough capability and feasibility for manufacturing of smoothly curved surface instead of conventional die forming method.

• 한국정밀공학회지
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• 제12권8호
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• pp.114-121
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• 1995

This paper describes a method which uses rail curves for blending surfaces. Blending surface between the free form surfaces which have the flexible shapes and are widely used today is investigated. The rail curves give blending surface continuty through Pointwise interpola- tion. It is the point in this paper that the blending surfaces give a good flexibility to modeling of base free form surfaces. Using rail curves for simple base surfaces, complicated models can be designed. Also this blending surfaces can be used for path generation in compoud surfaces.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2022년도 추계학술대회
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• pp.113-114
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• 2022

본 연구는 선박의 내부의 비금속 재질 등으로 인하여 표면파 공진기의 설치가 어려운 환경에서 이를 극복하는 방법으로 플렉서블 기판을 이용한 표면파 공진기의 적용 가능성에 대하여 제작 및 실험을 통해 확인하였다. 설계 제작된 플렉서블 공진기의 곡면구조에서 실험한 결과 평면구조에서 평면형 공진기보다 성능은 열화되지만, 곡면구조에서 평면형 공진기 대비 높은 전송속도를 확인하여 그 적용 가능성을 확인하였다. 본 실험을 통해 평면형 표면파 공진기가 부착되기 어려운 구조물에서도 금속체 표면파 통신이 가능할 것으로 생각되며, 선실 선교 등 내부가 비금속 포장재로 되어 있는 공간에서도 내부의 연결된 금속 파이프를 통해 선박 전 구간에서 최적의 금속체 표면파 통신 구성이 가능할 것으로 생각한다.

• 소성∙가공
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• 제21권7호
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• pp.432-440
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• 2012

In this article, the design of the flexible forming process considering die shape compensation using an iterative over-bending method based on numerical simulation was conducted. In this method, the springback shape obtained from the final step of the first forming simulation is compared with the desired objective shape, and a shape error is calculated as a vector norm with three-dimensional coordinates. The error vector is inversely added to the objective surface to compensate both the upper and lower flexible die configurations. The flexible die shapes are recalculated and the punch arrays are adjusted according to the over-bent forming surface. These iterative procedures are repeated until the shape error variation converges to a small value. In addition, experimental verification was conducted using a 2000-kN flexible forming apparatus for thick plates. Finally, the configuration of the prototype obtained from the experiment was compared with the numerical simulation results, which had springback compensation. It is confirmed that the proposed method for compensating for the forming error could be used in the design of flexible forming of thick-curved plates.

• 센서학회지
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• 제33권2호
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• pp.86-92
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• 2024

Flexible electronic devices are exposed to repeated mechanical deformation; therefore, electrode performance is an important element. Recently, a new technology has been developed to improve the adhesion strength between polymer substrates and metal thin films through the cross-linking reaction of bovine serum albumin (BSA) bioconjugation proteins; however, additional performance evaluation as an electrode is necessary. Therefore, in this study, we investigated the effect of adhesive strength between a flexible substrate and a metal thin film on the performance of a flexible electrode. Cracks and changes in the electrical resistance of the electrode surface were observed through outer bending fatigue tests and tensile tests. As a result of a bending fatigue test of 50,000 cycles and a tensile test at 10% strain, the change in the electrical resistance of the flexible electrode with a high adhesion strength was less than 40%, and only a few microcracks were formed on the surface; thus, the electrical performance did not significantly deteriorate. Through this study, the relationship between the adhesion strength and electrical performance was identified. This study will provide useful information for analyzing the performance of flexible electrodes in the commercialization of flexible electronic devices in the future.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.547-551
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• 1996

In this paper, robust vibration control of a one-link flexible robot arm based on variable structure system is discussed. We derive dynamic equations of it using a Lagrangian assumed modes method based on Bernoulli-Euler Beam theory. The optimal sliding surface is designed and the problem of chattering is also solved by the adoption of a continuous control law within a small neighborhood of the switching hyperplane.