• Title/Summary/Keyword: sliding contact

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Thermoelastic Finite Element Analysis of Double horizontal Subsurface Cracks Due to Sliding Surface Traction (마찰열을 고려한 미끄럼 접촉시 내부 복수 수평균열 전파해석)

  • 이진영;김석삼;채영훈
    • Tribology and Lubricants
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    • v.18 no.3
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    • pp.219-227
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    • 2002
  • A linear elastic fracture mechanics analysis of double subsurface cracks propagation in a half-space subjected to moving thermomechanical surface traction was performed using the finite element method. The effect of frictional heat at the sliding surface on the crack growth behavior is analyzed in terms of the thermal load and peclet number. The crack propagation direction is predicted in light of the magnitudes of the maximum shear and tensile stress intensity factor ranges. When moving thermomechanical surface traction exists, subsurface horizontal cracks are propagation in-plane crack growth rate at the beginning but they are propagation out-of-plane crack growth rate by the frictional heat which is occurrence by the repeated sliding contact.

Thermoelastic Finite Element Analysis of Multiple horizontal Subsurface Cracks Due to Sliding Surface Traction (마찰열을 고려한 미끄럼 접촉시 내부 복수 수평균열 전파해석)

  • 이진영;김석삼
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.11a
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    • pp.50-58
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    • 2000
  • A linear elastic fracture mechanics analysis of multiful subsurface cracks propagation in a half-space subjected to moving thermomechanical surface traction was peformed using the finite element method. The effect of frictional heat at the sliding surface on the crack growth behavior is analyzed in terms of the thermal load and peclet number. The crack propagation direction is predicted in light of the magnitudes of the maximum shear and tensile stress intensity factor ranges. When moving thermomechanical surface traction exists, subsurface horizontal cracks are propagation in-plane crack growth rate at the beginning but they are propagation out-of-plane crack growth rate by the frictional heat which is occurrence by the repeated sliding contact.

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The Effects of Surface Roughness on Wear-life of DLC Coating in Dry Sliding (모재의 표면 거칠기가 DLC 코팅의 마멸수명에 미치는 영향)

  • Lee Young-Ze;Shin Kyung-Seob;Cho Chung-Woo
    • Tribology and Lubricants
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    • v.21 no.3
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    • pp.130-135
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    • 2005
  • Dry sliding wear resistance of DLC coated silicon disk with different surface roughness has been evaluated using a ball-on-disk sliding tester. It was found that the transfer layer formed on steel ball produced a low friction regime and the formation of transfer layer was more active with increasing the substrate surface roughness. Wear life of DLC coating was increased as increasing the real area of contact.

Wheel/Rail Contact Analysis with Consideration of Friction and Torque (마찰과 토크를 고려한 차륜/레일 접촉 해석)

  • Song, Ki-Seok;Han, Seung-Hee;Choi, Yeon-Sun
    • Journal of the Korean Society for Railway
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    • v.17 no.1
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    • pp.14-18
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    • 2014
  • Wheel/rail contact is a significant problem in railway dynamics. In this paper, the wheel/rail contact is examined analytically and numerically as a contact problem between two cylinders where torque and friction have effect. Furthermore, the contact of a real wheel and rail is investigated numerically where the normal and shear force act. This study demonstrates that the wheel/rail contact is a process that generates traction force through creep where rolling and sliding occurs simultaneously depending on the shape of the wheel and rail, and the friction coefficient between them.

A Comparative Study on Eigen-Wear Analysis and Numerical Analysis using Algorithm for Adaptive Meshing (마모해석을 위한 고유치해석과 Adaptive Meshing 알고리듬을 이용한 수치해석 비교)

  • Jang, Ilkwang;Jang, Yong Hoon
    • Tribology and Lubricants
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    • v.36 no.5
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    • pp.262-266
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    • 2020
  • Herein, we present a numerical investigation of wear analysis of sliding systems with a constant speed subjected to Archard's wear law. For this investigation, we compared two methods: eigen-wear analysis and adaptive meshing technique. The eigen-wear analysis is advantageous to predict the evolution of contact pressure due to wear using the initial contact pressure and contact stiffness. The adaptive meshing technique in finite element analysis is employed to obtain transient wear behavior, which needs significant computational resources. From the eigen-wear analysis, we can determine the appropriate element size required for finite element analysis and the time increment required for wear evolution by a dimensionless variable above a certain value. Since the prediction of wear depends on the maximum contact pressure, the finite element model should have a reasonable representation of the maximum contact pressure. The maximum contact pressure and wear amount according to this dimensionless variable shows that the number of fine meshes in the contact area contributes more to the accuracy of the wear analysis, and the time increment is less sensitive when the number of contact nodes is significantly larger. The results derived from a two-dimensional wear model can be applied to a three-dimensional wear model.

Comparison of Rolling Contact Fatigue Life of Bearing Steel Rollers Lubricated with Traction Oil and Mineral Oil Corresponding to ISO VG32

  • Nakajima, A.;Mawatari, T.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.291-292
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    • 2002
  • Using a low viscosity synthetic traction oil and a low viscosity mineral oil with nearly equal viscosity grade of ISO VG 32, the effect of kind of oil on the fatigue life of bearing steel rollers was examined. A pair of rollers finished the contact surfaces to a mirror-like condition were driven under rolling with sliding conditions of s = -3.2% and a maximum Hertzian stress in the range of $P_H=2.8GPa{\sim}4.0GPa$ was applied in point contact condition. As a result of experiments, the fatigue life with a mineral oil was longer than that with a traction oil under higher stress conditions above $P_H=3.4GPa$. Based on the numerical calculation results of the thermal EHL which simulates the present experiment, the authors discuss the reason why such a difference in the fatigue life comes out.

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Wear characteristics depended on Wear Index in Wheel-Rail Interface (차륜 답면과 레일의 경계영역에서의 마모 특성)

  • Ahn, Jong-Gon;Kwon, Seok-Jin;Son, Young-Jin;Kim, Ho-Kyung
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.560-567
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    • 2011
  • Wheel and rail wear is a fundamental and complicate problem in railway field. The life of railway is usually limited by wear. The wheel surface is subjected to high normal and tangential contact stress. The removal of material from the surface by wear is function of the sliding and contact stress. In the present paper, the wear characteristic depended on slip rate, contact pressure and temperature are investigated and is used to twin disc tester. The result shows that the wear in wheel-rail interface is remarkably depended on slip rate and contact pressure.

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Wear Characteristics Depended on Wear Index in Wheel-Rail Interface (차륜 답면과 레일의 경계영역에서의 마모 특성)

  • Kim, Moon-Ki;Ahn, Jong-Gon;Kim, Sung-Kwon;Kwon, Seok-Jin;Lee, Hi-Sung
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1000-1007
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    • 2011
  • Wheel and rail wear is a fundamental and complicate problem in railway field. The life of railway is usually limited by wear. The wheel surface is subjected to high normal and tangential contact stress. The removal of material from the surface by wear is function of the sliding and contact stress. In the present paper, the wear characteristic depended on slip rate, contact pressure and temperature are investigated and is used to twin disc tester. The result shows that the wear in wheel-rail interface is remarkably depended on slip rate and contact pressure.

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Frictional Contact Analysis of the compression-Induced Crack Surfaces using the Finite element Method (유한요소법을 이용한 압축력으로 인한 균열 표면의 마찰접촉 해석)

  • 김방원;이기수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.517-522
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    • 2000
  • When a body including a crack inside is subjected to the compressive forces, the crack is closed and sliding occurs on the crack surfaces. In this work, a subsurface crack subjected to a static or moving compressive load is analyzed with the finite element method considering friction on the crack surface. The friction on the crack surface is assumed to follow the Coulomb friction law. A numerical method based on the finite element method and iterative method is applied in this work. And the result is compared with the frictional contact of crack by ANSYS using contact 12 element. The numerical results of two methods are compared with the wellknown analytical solutions, and the accuracy of iterative method is checked..

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Analysis of Line and Circular Contact Elastohydrodynamic Lubrication with Multigrid Multilevel Method (다중 격자 다중 차원법을 이용한 선접촉 또는 점접촉 탄성 유체 윤활 해석)

  • 장시열
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1999.11a
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    • pp.323-330
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    • 1999
  • The conventional analysis for the numerical computation of fluid film thickness with elastic deformation of contact region. is performed by Newton-Rephson method for its 18st convergence characteristics. However, both high load and relatively low sliding velocity frequently make it impossible for Newton-Rahpson method to get both converged and stable solutions. In particular, this method cannot provide converged Solution under the condition of high load above 1.0 GPa which frequently occurs in line contact of EHL problem. Multigird multi-level method for the solver of non-linear partial differential equation including solid deformation is preferred to Newton-Rshpson method for better convergence and stability and is applied to line contact EHL behavior in this study.

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