• Title/Summary/Keyword: 비드력

Search Result 49, Processing Time 0.025 seconds

Optimum Design of Draw-bead Force in Sheet Metal Stamping using Rigid-plastic FEM and Responses Surface Methodology (강소성 유한요소해석과 반응표면분석법을 이용한 박판성형공정에서의 드로우 비드력 최적설계)

  • Kim, Se-Ho;Huh, Hoon;Tezuka, Akira
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 1999.03b
    • /
    • pp.143-148
    • /
    • 1999
  • Design optimization is performed to calculated the draw-bead force for satisfying the design re-quirements. For an analysis tool a rigid-plastic finite element method with modified membrane element is adopted. response surface methodology is utilized for constructing the approximation surface for the optimum searching of draw bead force in sheet metal forming process. the algorithm developed is ap-plied to a design of the draw bead forces in a deep drawing process. The results show that the design of process parameters is applicable in complex metal forming analysis. It is also noted that the present algo-rithm enhances the stable optimum solution with small times of optimization iteration.

  • PDF

Characteristics on non-shielding Nd:YAG Laser Welding of 69TR-R and CHSP60C, 600MPa grade steels - Comparison of characteristics on bead on plate welded part - (600MPa급 60TR-R 및 CHSP60C의 난실드 Nd:YAG 레이저에 따른 특성 비교 - 비드 온 플래이트 용접부 특성의 비교 -)

  • 권민석;한태교;김병익;이봉근;강정윤;정병훈
    • Proceedings of the KWS Conference
    • /
    • 2004.05a
    • /
    • pp.100-102
    • /
    • 2004
  • 인장강도 600MPa 이상을 가지는 TRIP형 고장력 강판인 60TR-R과 석출경화형 합금인 CHSP60C는 자동차용 소재로 주목을 받고 있다. 또한 레이저 용접은 열 변형이 적고 비드 외관이 미려할 뿐만 아니라 연속 및 고속 용접이 가능하여 생산성 및 정밀성, 안정성이 높아 자동차조립 및 부품 제조공정에 적용되고 있다. (중략)

  • PDF

A Study on the Drawing characteristics of Sheet through Step Drawbead (계단형 드로오비드에 의한 판재의 인출특성에 관한 연구)

  • 박원배;김창만;김낙수;서대교;전기찬
    • Transactions of Materials Processing
    • /
    • v.5 no.2
    • /
    • pp.130-137
    • /
    • 1996
  • The sheet formability can be improved by the optimum drawbeads installation because draw-beads can control the flow of the metal into the die cavity when the punch enters into the die opening, In this study the drawing characteristics for step drawbead are analyzed by 2-D rigid -plastic FEM and also are measured experimentally. In addition for the validity of FEM theoretical results are compared with the experimental results. Especially the draw bead restrain-ing forces and the strain distributions of drawn specimens are obtained in both FEM and experiment. Also the effects of the drawbead dimensions drawing angles and blank holding forces on the drawing characteristics are investigated.

  • PDF

Effect of various surface roughness of steel sheet on characteristic of surface friction in stamping (판재의 표면 거칠기에 따른 표면 마찰 특성 변화)

  • 조상헌;허보영;아라이히로시;주상응;김상열;이용진;문만빈;이영수;고흥석
    • Proceedings of the Materials Research Society of Korea Conference
    • /
    • 2003.03a
    • /
    • pp.24-24
    • /
    • 2003
  • 최근 자동차 산업이 발달함에 따라 철강업계와 자동차 회사에서는 전에 많이 사용하던 내연 무도금강판 대신 부식에 저항력이 강한 도금강판을 사용한 이후로 냉연강판의 가공 시에 야기되지 않았던 많은 문제점들이 나타났다 자동차용 강판의 경우 판재의 체적에 비하여 금형과 판재의 접촉면적이 큰 프레스 공정에서는 판재의 표면에 작용하는 마찰력의 크기가 판재의 스탬핑 성형성에 큰 영향을 미친다. 이는 마찰특성이 비록 재료고유의 성형한계에서는 영향을 미치지 못하나 스탬핑 공정에 있어서 금형과의 접촉면에서 마찰력의 크기가 패널의 변형률분포를 변화시켜 스탬핑 성형성에 큰 영향을 주는 것이다. 따라서 본 연구는 자동차용 도금강판의 표면 거칠기에 따른 판재의 표면 마찰 특성 변화를 알아보았다. 소재의 기계적 특성 측정은 UTM을 사용하였고, 도금층은 XRD, SEM을 이용하여 상분석 하였으며, 표면 거칠기는 AFM(Atomic Force Microscope), SJ-400(Mitutoyo)을 사용하여 표면 거칠기를 측정하였다. 또 드로잉 하중을 비드부에서의 굽힘-굽힘 풀림 소성변형에 의한 변형력 성분과 마찰력 성분으로 분리하여 강판의 쿠롬 마찰계수를 DBS(Draw bead simulation)로 측정하였다.

  • PDF

Study on the Measurement of Restraining and Opening Forces in Drawbeads (드로우비드 상압력과 인출력 측정에 관한 연구)

  • Moon, S.J.;Keum, Y.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2006.05a
    • /
    • pp.203-206
    • /
    • 2006
  • The drawbeads, which is used for controlling the flow of the sheet by imposing the tension and for preventing the springback in the sheet metal forming process, affects a lot the formability because of the differences in the restraint and opening forces according to the drawbead shapes and dimensions. In this study, the experimental device enabling to measure the drawbead restraining forces and the drawbead opening forces associated with various drawbead shapes and dimensions and their theoretical evaluation are introduced and verified through the experimental measurement of those of a circular drawbead.

  • PDF

An Analysis of Thermal Stress and Angular Distortion in Bead-on-Plate Welding Incorporating Constrained Boundary Conditions (판재의 비드 용접에서 구속경계조건을 적용한 열응력 및 각변형 해석)

  • 배강열;최태완
    • Journal of Welding and Joining
    • /
    • v.17 no.1
    • /
    • pp.104-115
    • /
    • 1999
  • There have been many studies on the two dimensional thermo-elasto-plastic analysis in welding process, mostly from viewpoint of residual stresses. In this study, the temperature distribution, transient thermal stress, and angular distortion during bead-on-plate gas metal arc welding of rectangular plates were analyzed by using the finite element method. A nonlinear heat transfer analysis was first performed by taking account of the temperature-dependent material properties and convection heat losses on the surface. This was followed by a thermo-elasto-plastic stresses and distortion analysis that incorporates the constrained boundary condition of the two dimensional solution domain to get the three dimensional size effect of the plate. The constrained boundary conditions adopted in this study were the constant displacement condition over the whole two dimensional section for axial movement in the welding direction, and the force boundary condition for rotational movementof the domain around the axis of the welding direction. It could be revealed that the theoretical predictions of the angular distortion have an improved agreement with the experimentally obtained data presented in the previous study.

  • PDF

Changes in Inequal Trading Practices due to Changes in Contents Production System (방송콘텐츠 제작방식 변화에 따른 불공정 관행 변화; 외주제작사 입장을 중심으로)

  • Roh, Dong-Ryul
    • The Journal of the Korea Contents Association
    • /
    • v.17 no.5
    • /
    • pp.540-551
    • /
    • 2017
  • While the way broadcasting contents are made has changed drastically, some conflicts appear to remain unchanged. And they are about allegedly unfair practices. The whole arguments may even be deemed natural to a certain degree, considering the characteristics of the overall creative industry. But it needs to be highlighted the conflicts are being aggravated both in drama and non-drama production industries for different reasons. The drama side of the issue comes from how the project-based organizations are organized, and will be resolved if broadcasting companies do not send over their directors. On the other hand, the non-drama side's issues are about the complaints that outsourcing production companies have about the production cost. In general, due largely to the genre's relatively weak power to generate revenue, the producers do not get the upper hand when it comes to the negotiations over financial matters.

Syntheses and Properties of Isosorbide-based Cationic Gemini Surfactants (이소소르비드 기반의 양이온 제미니 계면활성제 합성 및 물성)

  • Cho, Jung-Eun;Jeong, Noh-Hee
    • Applied Chemistry for Engineering
    • /
    • v.31 no.4
    • /
    • pp.429-437
    • /
    • 2020
  • In this study, a cationic gemini surfactant was synthesized using isosorbide, in order to modify the alkyl chain length in the range of C10~C16. The c.m.c and surface tension of the synthesized cationic gemini surfactant were measured to be in the ranges of 5.13 × 10-4~1.62 × 10-4 mol/L and 31.86~37.41 dyne/cm, respectively. The surface tension increased with increasing the length of the alkyl group. In addition, as the area per molecule occupied by the surfactant adsorbed on the interface increased with the reduced extent of adsorption, the bubble generation at the air-water interface decreased. The emulsifying capacity in benzene was maintained above 60 ± 5% after 8 h while that in soybean oil tended to decrease above 50 ± 5%. The performance was superior in benzene, a highly hydrophobic substance, and the emulsion stability was shown to be consistent beyond 1 h during the preparation of pre-emulsion in oil and water. The antimicrobial activity was dependent on the length of the hydrophobic chain of the synthesized cationic gemini surfactant due to the increased size of the clean zone in Escherichia coli (E.coli) and Staphylococcus aureus.

Application and Type of Magnetic Separator (자력선별장비의 유형과 활용)

  • Lee, Sang-hun;Yang, Injae;Choi, Seungjin;Park, Jayhyun
    • Resources Recycling
    • /
    • v.27 no.6
    • /
    • pp.11-22
    • /
    • 2018
  • Magnetic separators has been used in the mining and the recycling fields in general, and is still applied in wide variety of fields. It is classified into the equipments for separating coarse ferrous scrap from non-ferrous materials and the equipments for concentrating fine ferromagnetic particles below 3mm. Magnetic separation equipments for concentrating fine materials also falls into two categories of low intensity and high intensity magnetic separators. The former is used for ferromagnetic materials but also paramagnetic materials of high magnetic susceptibility, and the latter for paramagnetic materials of lower magnetic susceptibility. Both low and high intensity magnetic separators could be utilized either dry and wet. Recently, the High gradient magnetic separators(HGMS) used in the range of less than 0.7 tesla has been gradually replaced by the magnetic separator made of rare earth permanent magnets commercialized in the 1980s. In addition, the expansion of nanotechnology in terms of synthetic magnetic materials in the environmental and biological fields is expected to contribute positively to the development of magnetic separation technology.

An Experimental Study on the Treatment of Organic Wastewater by Soil Microbes Using Three-phase Fluidized Bed (삼상유동층 반응기에서 토양미생물에 의한 유기성 폐수처리에 관한 연구)

  • Choung, Youn Kyoo;Chun, Yang Kun
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.12 no.1
    • /
    • pp.207-217
    • /
    • 1992
  • In this study, isolated and cultured nitrogen fixed microbes were seeded in the three-phase fluidized bed in which gas, solid and liquid were contacted directly. Input velocity was varied from 8.12 cm/hr to 16.32 cm/hr. And upflow gas pressure was fixed to 80 psi. Return ratios were from 0.2 to 0.6 with the each experimental condition. According to these condition, movement of media, growth of biofilm and removal efficiency were measured. As the results, in case of briquette ash, biofilm was developed to $170{\mu}m$ when velocity was 8.12 cm/hr and return ratio was 0.6. In this condition, COD removal efficiency was 97% and $NH_4$-N removal efficiency was 83%. At the same condition, biofilm thickness of glass bead was $17.59{\mu}m$ and its COD and $NH_4$-N removal efficiency was 83% and 72%. Nitrogen fixed microbes have following characters: it formed dark-brownish sludge, excellent adhesive force, easy solid-liquid separation and low oxygen uptake ratio, but sensitive to DO concentration. Not only it endured shock loading, but required short time to steady state.

  • PDF