• Title/Summary/Keyword: Subsurface Stress

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Subsurface Stress Analysis with the Consideration of Tangential Loading and Elasto-Hydrodynamic Lubrication (탄성유체 윤활상태와 접선하중을 고려한 접촉표면 내부의 응력해석)

  • 구영필
    • Tribology and Lubricants
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    • v.20 no.4
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    • pp.190-196
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    • 2004
  • The effect of tangential loading on the subsurface stress field has been investigated numerically. As tangential load increases, the subsurface stress field expands more widely to the direction of the tangential load. Places of the maximum shear stress and the maximum effective stress are getting closer to the surface with the increasing tangential load. The tangential load in an elasto-hydrodynamic lubrication condition is so low that it does not affect the subsurface stress field.

The Subsurface Stress Field Caused by Both Normal Loading and Tangential Loading

  • Koo Young- Phi;Kim Tae-Wan;Cho Yong-Joo
    • Journal of Mechanical Science and Technology
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    • v.19 no.11
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    • pp.1967-1974
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    • 2005
  • The subsurface stress field caused by both normal loads and tangential loads has been evaluated using the rectangular patch solution. The effect of tangential loading on the subsurface stress field has been investigated in detail for both the cylinder-on-cylinder contact and a spur gear teeth contact. For the cylinder-on-cylinder contact, the subsurface stress fields are moved more to the direction of tangential loads and the positions where the maximum stress occur are getting closer to the surface with the increasing tangential loads. The subsurface stress fields of the gear teeth contact are expanded more widely to the direction of tangential loads with the increasing tangential loads. The friction coefficient of a gear teeth contact is low because they are operated in a lubricated condition, and therefore surface tractions in the EHL condition hardly affect on the subsurface stress field.

Subsurface stress field beneath the cam-roller contact surface under elastohydrodynamic lubrication and tangential loading (탄성유체윤활 및 접선하중 상태에서 캠-롤러 접촉표면의 내부 응력장)

  • Kim Hyung-Ja;Kim Young-Dae;Park Kyung-Dong;Koo Young-Pil
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2004.11a
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    • pp.261-268
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    • 2004
  • For cam and roller-follower contacting surfaces, the effect of tangential loading on the subsurface stress field at an elaso-hydrodynamic lubrication condition has been studied numerically. As tangential load increases, the subsurface stress field extended more widely to the direction of the tangential load. The positions of the maximum shear stress and the maximum effective stress are getting closer to the surface with the increasing tangential load. The tangential load at the elasto-hydrodynamic lubrication condition is of little consequence to the subsurface stress field.

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An Analysis on the Residual Stress of Subsurface Zone due to Rolling Contact (회전접촉에 의해 발생하는 Subsurface Zone의 잔류응력에 관한 해석)

  • Gang, Gye-Myeong;Kim, Seon-Jin
    • Korean Journal of Materials Research
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    • v.3 no.1
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    • pp.58-64
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    • 1993
  • The degree of work hardening in the subsurface zones varied with the experimental conditions under the rolling contact fatigue wear test of high carbon Cr-Ti alloy steel was evaluated by the distribution of residual stresses. Surface residual stresses before the test did not affect the wear property. Surface residual stresses after the test decreased by the increase of contact stress and running. velocity. but the maximum compressive residual stress and its depth of saturation in the subsurface zone increased. The relationship between these experimental results and the distribution of the theoritical shear stress was also discussed.

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Stress Intensity factor Analysis for Three-Dimensional Cracks in Inhomogeneous Materials (비균질재료의 3차원 균열에 대한 응력확대계수 해석)

  • 김준수;이준성
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.4
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    • pp.197-203
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    • 2003
  • Accurate stress intensity factor analyses and crack growth rate of surface -cracked components in inhomogeneous materials are needed fur reliable prediction of their fatigue life and fracture strengths. This paper describes an automated stress intensity factor analysis of three-dimensional (3D) cracks in inhomogeneous materials. 3D finite element method (FEM) was used to obtain the stress intensity factor fur subsurface cracks and surface cracks existing in inhomogeneous materials. To examine accuracy and efficiency of the present system, the stress intensity factor for a semi-elliptical surface crack in a plate subjected to uniform tension is calculated, and compared with Raju-Newman's solutions. Then the system is applied to analyze cladding effect of subsurface cracks in inhomogeneous materials. The results were compared with those surface cracks in homogeneous materials. It is clearly demonstrated from these analyses that the stress intensity factors for subsurface cracks are less than those of surface cracks. Also, this system is applied to analyze cladding effect of surface cracks in inhomogeneous materials.

Stress Intensity Factor Analysis for Surface Crack in Inhomogeneous Materials (비균질재료의 표면균열에 대한 응력확대계수 해석)

  • 김준수;이준성
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.816-819
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    • 2002
  • Accurate stress intensity factor analyses and crack growth rate of surface-cracked components in inhomogeneous materials are needed for reliable prediction of their fatigue lift and fracture strengths. This paper describes an automated system for analyzing the stress intensity factors of three-dimensional (3D) cracks in inhomogeneous materials. 3D finite element method (FEM) was used to obtain the stress intensity factor for subsurface cracks and surface cracks existing in inhomogeneous materials. To examine accuracy and efficiency of the present system, the stress intensity factor for a semi-elliptical surface crack in a plate subjected to uniform tension is calculated, and compared with Raju-Newman's solutions. Then the system is applied to analyze cladding effect of subsurface cracks in inhomogeneous materials. The results were compared with those surface cracks in homogeneous materials. It is clearly demonstrated from these analyses that the stress intensity factors for subsurface cracks are less than those of surface cracks.

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Finite Element Analysis of the Inclined Subsurface Cracks in a Homogeneous Body Under a Moving Compressive Load

  • Lee, Kyung-Sick;Chung, Gyu-Sung
    • KSTLE International Journal
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    • v.5 no.1
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    • pp.7-13
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    • 2004
  • The inclined subsurface cracks in a homogeneous body subjected to a moving compressive load is analyzed with the finite element method (FEM) considering friction on the crack surface. The stress intensity factors for the inclined subsurface cracks are evaluated numerically for various cases such as different inclined angles and changes in the coefficient of friction. The effects of the inclined angle and the coefficient of friction on the stress intensity factor are discussed. The difference between the behaviors of the parallel subsurface crack and those of the inclined subsurface crack is also examined.

Stress Analysis on the Cam-Roller Contact Parts in a Marine Diesel Engine (박용 디젤기관 캠-롤러 접촉부의 응력 해석)

  • 김형자;임우조;조용주;구영필
    • Journal of Advanced Marine Engineering and Technology
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    • v.26 no.2
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    • pp.174-180
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    • 2002
  • The subsurface stress field beneath the roller's contacting surface due to the contact pressure in lubricating condition has been calculated. Main purpose of this study in view of engineering is to prove the validity of the numerical profile roller presented by Koo et al. The Love's rectangular patch solution was used to obtain the subsurface stress field. The stress field of the numerical profile roller was compared with the one of the existing dub-off profile roller The analysis results show reduced subsurface stresses for the numerical profile roller.

Finite Element Analysis of Subsurface Multiple Horizontal Cracks Propagation in a Half-space Due to Sliding Contact (유한요소법을 이용한 미끄럼 접촉시 내부 복수 수평균열 전파해석)

  • 이상윤;김석삼;권영두
    • Tribology and Lubricants
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    • v.16 no.5
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    • pp.373-380
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    • 2000
  • Finite element analysis is performed on the subsurface crack propagation in brittle materials due to sliding contact. The sliding contact is simulated by a rigid asperity moving across the surface of an elastic half-surface containing single and multiple cracks. The single crack, coplanar cracks and parallel cracks are modeled to investigate the interaction effects on the crack growth in contact fatigue. The crack location is fixed and the friction coefficients between asperity and half-space are varied to analyze the effect of surface friction on stress intensity factor for horizontal cracks. The crack propagation direction is predicted based on the maximum range of shear and tensile stress intensity factors. With a coplanar crack, the stress intensity factor was increased. However, with a parallel crack, the stress intensity factor was decreased. These results indicate that the interaction of a coplanar crack increases fatigue crack propagation, whereas that of a parallel crack decreases it.

Optimization of the Gear Tooth Crowning Amount Considering Contact Subsurface Stress (표면아래응력을 고려한 기어이의 크라우닝 최적화에 관한 연구)

  • Lee, Sang-Don;Kim, Jong-Sung;Cho, Yong-Joo
    • Tribology and Lubricants
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    • v.25 no.1
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    • pp.38-42
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    • 2009
  • Gear is an essential component of an automotive. Crowning is used for tooth modification of a gear. The basic concept of gear tooth crowning is to reduce the stress concentration in edge of contact area and appropriate profile modifications can help gears to resist scoring, pitting, and tooth breakage. In this study, a method to determinate spur gear tooth crowning amount to make smooth surface stress and subsurface stress distribution is proposed. This method is based on the contact analysis.