• Title/Summary/Keyword: contacting stresses

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Coupled Thermal-Mechanical Analysis of Rubber Oil Seals (열응력을 고려한 고무 오일시일 해석)

  • 김청균;전인기
    • Tribology and Lubricants
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    • v.10 no.2
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    • pp.39-42
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    • 1994
  • This paper deals with the distributions of the contact stress in oil seals. The distributions of the contact stress due to the temperature effects are analyzed for various values of the interference for a nitrile rubber seal. The calculated FEM results show that the relative maximum stresses occur at the contacting area against the shaft, the flex zone, and the contacting area of the garter spring grooves. Using the coupled temperature-stress FEM a nalysis, the contact force of a radial lip seal with and without the garter spring are studied as a function of shaft diameter. The calculated results of mechanical analysis show good correspondence with those of the coupled thermal-mechanical analysis method except small values of the interference. And the calculated results indicated that the thermal stresses only have a very minor influence on the deformed shape of the lip seal as the interference increases. But the coupled temperature-stress analysis will be very useful tool to predict the contact behaviors of rubber lip seals for small values of the interference.

Methodology of tool analysis to improve the accuracy of cold forged parts (냉간단조품의 정밀도향상을 위한 금형해석 기법)

  • Kim, T.H.;Kim, B.M.;Park, J.C.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.1
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    • pp.29-37
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    • 1995
  • In many metal forming processes, it is common to use stress rings for reducing elastic deformation and failures of forming dies. But, shrink fit of dies inner diameter of die insert, machining is reuqired after shrink fit processes. The reduction of inner diameter can be predicted by the analysis of elastic-plastic finite element method. The dimension of dies before shrink fit can be determined to minimize or remove machining after shrink fit processes by deformation analysis of die. The computation of contacting stresses along die surface was analyzied by rigid plasitic finite element method, and data were interpolated by the contact search algorithm. In this paper, we propose the analysis method of forging dies after shrink fit and forming to improve dimensional accuracy of final products.

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The Fatigue Crack Initiation Life under the Rolling Contact of Rough Surfaces using Critical Plane Approach (임계평면법을 이용한 거친 표면의 구름접촉시 피로균열 시작수명)

  • 설광조;김태완;조용주
    • Tribology and Lubricants
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    • v.19 no.1
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    • pp.26-30
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    • 2003
  • The stresses of surface and substrate under the rough surface contact are irregular. Using rainflow counting method for irregular stresses, the fatigue surface crack initiation lift was calculated. With the surface generated by computer, this paper figures out the random load generated by contacting to the rough surface, analyzes the stress of its subsurface, and calculates the fatigue crack initiation life of the rough surface fatigue theory.

Optimization Design on the Sealing Surface Profiles of Contacting Seal Units (접촉식 시일장치의 밀봉 접촉면 형상에 대한 최적화 설계연구)

  • Kim, Chung-Kyun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.6
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    • pp.761-766
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    • 2011
  • In this study, the optimized design profiles between a seal ring and a seal seat of contacting seal units has been proposed based on the FEM computed results. The maximum temperatures, the thermal distortions in axial and radial directions, and maximum contact normal stresses between a seal ring and a seal seat have been analyzed for various contact sealing profiles. The FEM computed results present that the contact area between seal rings and seal seats is very important for a good tribological performance such as low friction heating, low wear, high contact normal stress in a primary sealing components. The seal surface model III in which has a small sealing contact area shows low dilatation of primary sealing components, and high contact stress between a seal ring and a seal seat. This model with small contact surface of a seal ring produces high friction heating and contact stress. But the model III produces very small deformations of contacting sealing surface because of high convection heat transfer by cooling water circulation around the seal ring surface. Thus, the analysis results recommend a short width of a primary sealing unit rather than a big width of contact surfaces of contacting seal units for reducing a leakage and axial deformation of primary seal components.

Fatigue Life Analysis on Multi-Stacked Film Under Thermal and Residual Stresses (열응력과 잔류응력하의 다층박막의 피로수명 해석)

  • Park Jun-Hyub
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.4 s.235
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    • pp.526-533
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    • 2005
  • Reliability problem in inkjet printhead, one of MEMS devices, is also very important. To eject an ink drop, the temperature of heater must be high so that ink contacting with surface reaches above $280^{o}C$ on the instant. Its heater is embedded in the thin multi-layer in which several materials are deposited. MEMS processes are the main sources of residual stresses development. Residual stress is one of the factors reducing the reliability of MEMS devices. We measured residual stresses of single layers that consist of multilayer. FE analysis is performed using design of experiment(DOE). Transient analysis for heat transfer is performed to get a temperature distribution. And then static analysis is performed with the temperature distribution obtained by heat transfer analysis and the measured residual stresses to get a stress distribution in the structure. Although the residual stress is bigger than thermal stress, thermal stress is more influential on fatigue life.

A Study on Stress Analysis of Spur Gear Using FEM (FEM을 이용한 스퍼기어 응력 해석에 관한 연구)

  • Lee, Kyung-Won;Ban, Jae-Sam;Kim, Gyu-Ha;Cho, Kyu-Zong
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.2
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    • pp.171-176
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    • 2002
  • This paper is the study on stress analysis of spur gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes compromising several cost effective and engineering advantages. The load transmission occurred by the contacting surfaces arises variable elastic deformations which are being evaluated through finite element analysis. The automatic gear design program is developed to model gear shape precisely. This gear design system developed was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when a pair of gear contact.

Stress Analysis for Tooth Modification of High Speed Gear (응력해석을 통한 고속기어 치형수정에 관한 연구)

  • 이경원;반제삼;김규하;조규종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.816-819
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    • 2002
  • This paper is the study on stress analysis for tooth modification of high speed gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes compromising several cost effective and engineering advantages. The load transmission occurred by the contacting surfaces arises variable elastic deformations which are being evaluated through finite element analysis. The automatic gear design program is developed to model gear shape precisely. This gear design system developed was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when gear tooth contacts. And this paper proposes method for the tooth modification after carrying out stress analysis using a finite element method.

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Stress Analysis for Tooth Modification (응력해석을 통한 치형수정에 관한 연구)

  • 이경원;반재삼;김규하;조규종
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.162-167
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    • 2003
  • This paper is the study on stress analysis for tooth modification of high speed gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes which compromise several cost effective and engineering advantages. The load transmission which occurred by the contacting surfaces arises variable elastic deformations evaluated through finite element analysis. The automatic gear design program was developed to model gear shape precisely. This developed gear design system was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when gear tooth contacts. And this paper proposes a method for the tooth modification after carrying out stress analysis using a finite element method.

Strength Analyses of New 2- and 3-Axis-Type Small Multiplying Gears in Dental Hand-Pieces (치과드릴 구동용 신 소형 2축 및 3축형 증속기어 강도특성 비교)

  • Kim, Cheol;Kim, Ju-Yeong;Lee, Jung-Ho;Kwak, Se-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.9
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    • pp.1027-1032
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    • 2012
  • Two types of very small multiplying gears and arrays have been developed for new dental hand-pieces, and the increased speed ratios, modules, number of teeth, gear diameters, and gear types were calculated based on the dynamics of the machinery. The contacting and bending strengths were evaluated for gear teeth with two design concepts using AGMA equations and finite element analyses, and the contacting stresses on teeth with and without DLC (diamond-like-carbon) coating layers were calculated. Fatigue and tension tests were performed to obtain an S-N curve, the Young's modulus, and the strength of the gear material, and these were utilized in the analyses. Slightly larger stresses were found for 2-axis-type gears than for other types of gears, and the S-N curves showed that a gear lifetime of 109 cycles was satisfied. The contacting stresses in gears coated with DLC were reduced by 30%. A new prototype model of a hand-piece with small gears was successfully fabricated and tested.

Contact problem for a stringer plate weakened by a periodic system of variable width slots

  • Mir-Salim-zada, Minavar V.
    • Structural Engineering and Mechanics
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    • v.62 no.6
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    • pp.719-724
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    • 2017
  • We consider an elastic isotropic plate reinforced by stringers and weakened by a periodic system of rectilinear slots of variable width. The variable width of the slots is comparable with elastic deformations. We study the case when the slots faces get in contact at some area. Determination of parameters characterizing the partial closure of variable width slots is reduced to the solution of a singular integral equation. The action of the stringers is replaced with unknown equivalent concentrated forces at the points of their connection with the plate. The contact stresses and contact zone sizes are found from the solution of the singular integral equation.