• Title, Summary, Keyword: contact stress

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Contact Stress Analysis of a Pair of Mating Spur Gears (스퍼기어의 접촉응력 해석)

  • Lee, Jin-Hwan;Lee, Dong-Hyong;Lee, Kwon-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.4
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    • pp.59-65
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    • 2010
  • This paper presents the study on the contact stress analysis of a pair of mating spur gears during rotation. Contact stress analysis is performed between two spur gear teeth at different contact positions during rotation. An example is presented to investigate the variation of contact stress on a pair of mating gears with contact positions. The variation of contact stress during rotation is compared with the contact stress at lowest point of single tooth contact(LPSTC) and AGMA Equation for contact stress. The results show that contact stress varies along the contact position and gets maximum values in the beginning and end of the contact. In this study, the gear design considering the contact stress on a pair of mating gears is more severe than that of AGMA standard.

Contact Stress Analysis of Helical Gear for Turbo Blower (터보블로워용 헬리컬 기어의 접촉응력 해석)

  • Hwang, Seok-Cheol;Lee, Dong-Hyong;Park, Young-Chul;Lee, Kwon-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.2
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    • pp.90-95
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    • 2011
  • This paper presents the study on the contact stress analysis of a pair of mating helical gears for turbo blower during rotation. Turbo blowers need high speed rotation of impeller in structure and high rate gear ratio. The use of helical gear indicated that noise was an important problem when the application involves high speeds and large power transmission. An example is presented to investigate the variation of contact stress on a pair of mating gears with contact positions. The variation of contact stress during rotation is compared with the contact stress at the lowest point of single tooth contact(LPSTC) and AGMA Equation for contact stress. In this study, the gear design considering the contact stress on a pair of mating gear is more severe than that of AGMA standard.

Stress Analysis of Epitrochoidal Gerotor for Hydraulic Motor (유압 모터용 에피트로코이드 제로터의 응력해석)

  • Kim, Du-In;Choe, Dong-Hun;An, Hyo-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.4
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    • pp.963-971
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    • 2000
  • Gerotor is a planar mechanism consisting of a rotor and lobes which form a closed space, namely a chamber. As active contact points between a rotor and lobes are subjected to very high contact stresses, wear in one or both of the rotor and lobe cannot be avoided. Therefore, in the design of Gerotor used in hydraulic motors a compromise between high torque output and contact stress is of great importance and a thorough analysis of design parameters should be conducted to achieve this compromise. In this study, a contact point is modelled as a linear spring in consideration of equivalent curvature to analyze the contact stress. As the contact stress calculation in this problem is a statically indeterminate type, a numerical iterative scheme has been adopted to obtain the solution. To fully understand the influence of design parameters on the contact stress, the relationship between pressure force, equivalent curvature, contact force and contact stress are analyzed. It is shown that the equivalent curvature of the contact point is a dominant factor that affects the maximum contact stress.

Conditions for Assuming Hertzian Stress for the Contact between a Circular Pin and Hole (원형 핀과 구멍의 접촉에서 헤르츠 응력장 가정을 위한 조건)

  • Kim, Hyung-Kyu
    • Tribology and Lubricants
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    • v.31 no.5
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    • pp.189-194
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    • 2015
  • This paper focuses on the conformal contact problem. A typical example of conformal contact is the contact between a pin and hole. In particular, this paper focuses on the condition for assuming a contact stress field to be a Hertzian pressure profile by using well-known classical solutions associated with Hertzian contact. Persson first developed the conformal contact analysis method around half a century ago, but there have been no significant improvements since then. The present research also adopted this method, but developed new solutions from the viewpoint of application to structural design. The analysis began with a comparison between Persson°Øs conformal contact stress and the Hertzian stress fields. The next step was to check the differences in the normalized stress values of both. This study used the tolerance for the difference in the peak stresses of Persson°Øs solution and the Hertz solution to validate the Hertzian assumption. This gave the range for the difference in radii of the pin and hole when the contact force and mechanical properties of the material are specified. The results showed that, at a tolerance of 5%, the Hertzian assumption is valid if half of the contact angle is less than 35°ý. In addition, the Hertzian assumption holds even for a relatively long contact length, in contrast to the general incomplete contact problem. This paper discusses these results along with other aspects of the application to the design.

Contact Characteristic and Stress Analysis of Wheel-Rail for Rolling Stock (철도차량용 휠과 레일의 접촉특성 및 응력 해석)

  • Sung, Ki-Deug;Yang, Won-Ho;Cho, Myoung-Rae;Kim, Cheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.5
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    • pp.148-156
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    • 2000
  • In this paper, we investigate contact characteristic of wheel-rail interface for rolling stock using the finite element method. Contact stress distribution due to the rail mounting slope is obtained in order to reduce the contact stress. Stress analysis of the rail, firstly, is performed one subjected to elliptical pressure based on Hertz theory. Secondly, we perform stress analysis of the rail subjected to contact stress obtained by this study. Results for the maximum shear stress, its location and the principal shear stress distribution are compared.

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Contact Stress Evaluations for the Ball Groove of Weiss Type Constant velocity joint (Weiss형 등속조인트 볼 홈의 접촉응력평가)

  • 김완두;이순복
    • Tribology and Lubricants
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    • v.5 no.2
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    • pp.60-67
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    • 1989
  • For the life prediction and fatigue failure prevention of the constant velocity joint, the maximum equivalent stress and its location in depth from the contact area are essential. These values give the fundamental information to determine the depth of the surface hardening treatment at the contact area. Contact stresses are evaluated at the surface and subsurface of the ball groove of the Weiss type constant velocity joint. The maximum contact pressure and the maximum equivalent stress are obtained. The effects of various parameters such as the radius of ball groove, friction coefficient, and residual stress are studied. The maximum equivalent stress and the maximum contact pressure increase as the radius of the ball grove increases. The location of the maximum equivalent stress moves toward surface as the friction coefficient increases. It was also found that the maximum equivalent stress becomes minimum when the compressire residual stress is about 0.16 times of the maximum contact pressure.

Study on the Stress Singularity of Interface Crack by using Boundary Element Method (경계요소법을 이용한 계면균열의 응력특이성에 관한 고찰)

  • Cho, Chong-Du;Kwahk, Si-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.4
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    • pp.197-204
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    • 1999
  • The boundary element method was used for studying singularities of an interface crack with contact zones. The iterative procedure is applied to estimate the contact zone size. Because the contact zone size was extremely small in a tension field, a large number of Gaussian points were used for numerical integration of the Kernels. Stress extrapolation method and J-integral were used ofr determining stress intensity factors. When the interface crack was assumed to have opened tips, oscillatory singularities appear near the tips of the interface crack. But the interface crack with contact zone which Comninou suggested had no oscillatory behavior. The contact zone size under shear loading was much larger than that under tensile. The stress intensity factors computed by stress extrapolation method were close to those of Comninou's solution. And the stress intensity factor evaluated by J-integral was similar to that by stress extrapolation method.

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A Study on the Contact Fatigue Life Evaluation for Railway Wheels Considering Residual Stress Variation (잔류응력 변화를 고려한 철도차량 차륜의 접촉피로 수명평가)

  • Seo, Jung-Won;Goo, Byeong-Choon;Choi, Jae-Boong;Kim, Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.9
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    • pp.1391-1398
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    • 2004
  • Railway wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles became more severe in recent years due to the increase of speed. Therefore, a more precise evaluation of wheelset life and safety has been requested. Wheel/rail contact fatigue and thermal cracks due to braking heat are two main mechanisms of the railway wheel failure. In this paper, an evaluation procedure for the contact fatigue life of railway wheel is proposed. One of the main sources of the contact zone failure is the residual stress. The residual stress on wheel is formed during the manufacturing process which includes a heat treatment, and then is changed by contact stress developed by wheel/rail contact and thermal stress induced by braking. Also, the cyclic stress history for fatigue analysis is determined by applying finite elements analysis for the moving contact load. The objective of this paper is to estimate fatigue life by considering residual stress due to heat treatment, braking and repeated contact load, respectively.

Numerical Analysis of the Contact Stress Behaviour in Scraper Seals (스크레이퍼 시일의 접촉응력 거동에 관한 수치적 연구)

  • 나윤환;김청균;류병진;유인석
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.198-203
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    • 1997
  • This paper deals with a numerical study of the tribological contact stress distributions of elastomeric lip seah for oscillating shafts when the sealing interference and band width between the lip edge of contact seals the shaft are present. Using the finite element method, the contact stress and band width of scraper seals rare analyzed for the sealing interference including some nonlinearities such as geometrical nonlinearity, material nonlinearity and nonlinear contact boundary condition. The FEM results showed that the contact stress concentrated on the contacting lip zone between the contacting edge of lip and the shaft for the increased interference. In double lip scraper seals, the maximum contact stress of the dust lip, which is used to exclude foreign contaminants, is six times higher than that of the primary sealing lip, which is used to contain lubricants.

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Finite Element Analysis of the Contact Stress Characteristics in Scraper Seals (스크레이퍼 실의 접촉응력 특성에 관한 유한요소해석)

  • Kim, Chung-Kyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.6
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    • pp.895-902
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    • 1999
  • This paper deals with a numerical study of the tribological contact stress distributions of elastomeric lip seals for oscillating shafts when the sealing interference and band width between the lip ease or contact seals and the shaft are present. Using the finite element method the contact stress and band width of scraper seals are analyzed for the sealing interference including some nonlinearities such as geometrical nonlinearity, material nonlinearity and nonlinear contact boundary condition. The FEM results showed that the contact stress concentrated on the contacting lip zone between the contacting edge of lip and the shaft for the increased interference. In double lip scraper seals, ole maximum contact stress of the dust lip, which is used to exclude foreign contaminants is six times higher than that of the primary sealing lip, which is used to contain lubricants.