• 제목/요약/키워드: Stretching Sheet

검색결과 80건 처리시간 0.021초

Analysis of Plasma Treatment Effects on a Compliant Substrate for High Conductive, Stretchable Ag Nanowires

  • Jeong, Jonghyun;Jeong, Jaewook
    • Applied Science and Convergence Technology
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    • 제27권1호
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    • pp.5-8
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    • 2018
  • In this paper, plasma treatment effects on a ploy(dimethyl siloxane) substrate were analyzed for the applications of stretchable silver nanowire (Ag NWs) electrodes. The oxygen plasma treated sample shows the best performance compared to nitrogen treated and untreated samples. The lowest sheet resistance and reasonable stretching capability was achieved up to 20% strain condition without open circuit fail for the oxygen plasma treated sample.

바인더 랩의 대변형 계산을 위한 효과적인 반복법 (An Effective Iteration Method for the Large Deformation Calculation of a Binder Wrap)

  • 오형석;금영탁;임장근
    • 한국자동차공학회논문집
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    • 제1권1호
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    • pp.140-148
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    • 1993
  • When a large automobile sheet metal part is formed in a draw die, the binder wrap is first calculated to predict the initial punch contact location for avoiding wrinkles and severe stretching of its thin blank sheet. Since the boundary of a pseudo blank in calculating a binder wrap by means of a geometrically nonlinear finite element method is unknown in advance, an iteration method is generally used. This paper presents an effective iteration method for correction of the pseudo blank in a binder wrap calculation. For the performance test, two examples are adopted. The calculated results for both examples show the good convergence which wasted solutions are obtained in the second iteration step.

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변형경로를 고려한 이방성 박판의 성형한계 예측 (Prediction of Forming Limits for Anisotropic Sheet Metals with Considering the Effect of Strain-Path Changes)

  • 손현성;정승호;김영석
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 추계학술대회 논문집
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    • pp.109-112
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    • 2000
  • This paper presents an analytical study that can predict the path-dependent forming limits for bilinear strain paths. To predict the forming limit diagrams(FLD), the analytical procedure was performed within the framework of Marciniak and Kuczynski approach by introducing the effect of the existence of strain gradient over the stretching punch. The predicted path-dependent forming limits of an anisotropic sheet were compared with the published experimental results. It was found that the predicted path-dependent forming limits were in good agreement with the experimental data.

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결함 성장을 고려한 수치해석적 성형한계도 예측 (A Numerical Prediction of the Forming Limit Diagram Considering Damage Evolution)

  • 김경태;송정한;이근안;이형욱;김세호;이용신
    • 소성∙가공
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    • 제18권8호
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    • pp.596-600
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    • 2009
  • Finite element simulation is an alternative method to practically find the forming limit diagram(FLD). In this paper, the novel fracture criterion is utilized to predict the FLD in conjunction with finite element analysis for sheet forming. The principal scheme of the fracture criterion in this paper is that growth of the micro voids leads up to fracture in the viewpoint of micro-mechanics. The numerical FLD is verified by results of the out-of plane stretching test using hemispherical punch. The verification is also conducted about two types of material. These results are in good accord with the experimental results. Especially, the proposed scheme is appropriate to predict FLDs for a restricted material with low ductility after the instability point or ultimate tensile strength.

금속 판재의 성형한계도 시험법에 관한 연구 (A Study on the Forming Limit Diagram Tests of Metal Sheets)

  • 장욱경;장윤주;김형종
    • 산업기술연구
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    • 제30권A호
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    • pp.49-57
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    • 2010
  • A forming limit diagram (FLD) defines the extent to which specific sheet material can be deformed by drawing, stretching or any combination of those two. To determine the forming limit curve (FLC) accurately, it is necessary to perform the tests under well-organized conditions. In this study, the influence of several geometric or process parameters such as the blank shape and dimensions, strain measuring equipments, test termination time, forming speed and lubricants on the FLC is investigated.

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자동차 YOKE 제품의 타원용기 성형에 관한 연구 (A Study on Elliptical Cup Drawing of YOKE Products for Automobile)

  • 박동환;배원락;박상봉;강성수
    • 한국정밀공학회지
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    • 제18권8호
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    • pp.182-192
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    • 2001
  • During the deep drawing process an initially flat blank is clamped between the die and the blank holder after which the punch moves down to deform the clamped blank into the desired shape. In general, sheet metal forming may involve stretching, drawing, bending or various combinations of those basic modes of deformation. The deformation problems of sheet metal working involve non-linearity in geometry and material. In this work, The punch load and thickness strain of electro-galvanized sheet steel (SECD) for elliptical deep drawing are examined under the various process conditions including, punch shape radius, die shape radius. The changes of punch load and thickness strain distribution of the deformed elliptical cup are affected by the size of each die shape radius.

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박막/쉘 혼합요소를 이용한 박판성형 해석과 박막/쉘 판별조건에 관한 연구 (A Study on the Criterion for Membrane/Shell Mixed Element and Analysis of Sheet Metal Forming Problem)

  • 정동원;양경부
    • 한국해양공학회지
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    • 제12권2호통권28호
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    • pp.57-64
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    • 1998
  • This study is concerned with criterion for membrane to shell conversion in two-dimensional elastic-plastic finite element analysis using membrane/shell mixed element. It is well known that in the sheet metal forming some parts of the sheet deform under almost pure stretching (membrane) conditions, whereas other parts in contact with sharp tooling surfaces can develop significant bending strains. The membrane analysis has a short computational time however, in the membrane analysis the bending effects can not be condidered at all. On the other hand, the shell analysis allows the consideration of bending effects, but involves too much computational time. So Onatel),2), Yang et al3),4) developed the membrane/shell mixed element. Onate introduced the energy ratio parameter and Yang et al introduced the ratio of thickness to radius of curvature as the criterion. In the present study we propose a new criterion by using the angle between both side elements in the nodal point.

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Numerical and statistical analysis of Newtonian/non-Newtonian traits of MoS2-C2H6O2 nanofluids with variable fluid properties

  • Manoj C Kumar;Jasmine A Benazir
    • Advances in nano research
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    • 제16권4호
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    • pp.341-352
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    • 2024
  • This study investigates the heat and mass transfer characteristics of a MoS2 nanoparticle suspension in ethylene glycol over a porous stretching sheet. MoS2 nanoparticles are known for their exceptional thermal and chemical stability which makes it convenient for enhancing the energy and mass transport properties of base fluids. Ethylene glycol, a common coolant in various industrial applications is utilized as the suspending medium due to its superior heat transfer properties. The effects of variable thermal conductivity, variable mass diffusivity, thermal radiation and thermophoresis which are crucial parameters in affecting the transport phenomena of nanofluids are taken into consideration. The governing partial differential equations representing the conservation of momentum, energy, and concentration are reduced to a set of nonlinear ordinary differential equations using appropriate similarity transformations. R software and MATLAB-bvp5c are used to compute the solutions. The impact of key parameters, including the nanoparticle volume fraction, magnetic field, Prandtl number, and thermophoresis parameter on the flow, heat and mass transfer rates is systematically examined. The study reveals that the presence of MoS2 nanoparticles curbs the friction between the fluid and the solid boundary. Moreover, the variable thermal conductivity controls the rate of heat transfer and variable mass diffusivity regulates the rate of mass transfer. The numerical and statistical results computed are mutually justified via tables. The results obtained from this investigation provide valuable insights into the design and optimization of systems involving nanofluid-based heat and mass transfer processes, such as solar collectors, chemical reactors, and heat exchangers. Furthermore, the findings contribute to a deeper understanding of stretching sheet systems, such as in manufacturing processes involving continuous casting or polymer film production. The incorporation of MoS2-C2H6O2 nanofluids can potentially optimize temperature distribution and fluid dynamics.

2차원 박판성형공정 해석을 위한 강소성 외연적 유한요소 수식화 (Rigid-Plastic Explicit Finite Element Formulation for Two-Dimensional Analysis of Sheet Metal Forming Processes)

  • 안동규;정동원;정완진
    • 대한기계학회논문집A
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    • 제20권1호
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    • pp.88-99
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    • 1996
  • The explicit scheme for finite element analysis of sheet metal forming problems has been widely used for providing practical solutions since it improves the convergency problem, memory size and computational time especially for the case of complicated geometry and large element number. The explicit schemes in general use are based on the elastic-plastic modeling of material requiring large computataion time. In the present work, a basic formulation for rigid-plastic explicit finite element analysis of plain strain sheet metal forming problems has been proposed. The effect of some basic parameters involved in the dynamic analysis has been studied in detail. Thus, the effective ranges of parameters have been proposed for numerical simultion by the rigid-plastic explicit finite element method. A direct trial-and-error method is introduced to treat contact and friction. In computation, sheet material is assumed to possess normal anisotropy and rigid-plastic workhardening characteristics. In order to show the validity and effectiveness of the proposed explicit scheme, computations are carried out for cylindrical punch stretching and the computational results are compared with those by the implicit scheme as well as with a commercial code. The proposed rigid-plastic exlicit finite element method can be used as a robust and efficient computational method for analysis of sheet metal forming.

Nanochannels for Manipulation of DNA Molecule using Various Fabrication Molecule

  • Hwang, M.T.;Cho, Y.H.;Lee, S.W.;Takama, N.;Fujii, T.;Kim, B.J.
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제7권4호
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    • pp.254-259
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    • 2007
  • In this report, several fabrication techniques for the formation of various nanochannels (with $SiO_2$, Si, or Quartz) are introduced. Moreover, simple fabrication technique for generating $SiO_2$ nanochannels without nanolithography is presented. By using different nanochannels, the degree of stretching DNA molecule will be evaluated. Finally, we introduce a nanometer scale fluidic channel with electrodes on the sidewall of it, to detect and analyze single DNA molecule. The cross sectional shape of the nanotrench is V-groove, which was implemented by thermal oxidation. Electrodes were deposited through both sidewalls of nanotrench and the sealing of channel was done by covering thin poly-dimethiysiloxane (PDMS) polymer sheet.