• Tribology and Lubricants
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• 제19권6호
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• pp.357-364
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• 2003

The sub­surface stress field beneath the gear's contact surface caused by the contact pressure in lubricated condition has been calculated. To evaluate the influence of the clearance shape on the stress field, two kinds of tooth profile models were chosen. One is the conventional cylinder contact model and the other is the new numerical model. Love's rectangular patch solution was used to obtain the sub­surface stress field. The analysis results show that the sub­surface stress is quite dependent on both the contact pressure and the profile model. The maximum effective stress of the new model is lower than that of the old model. The depth where the maximum effective stress occurs in the new model is not proportional to the intensity of the external load.

• 대한기계학회논문집
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• 제11권2호
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• pp.198-204
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• 1987

본 논문에서는 전보에서 창성된 인벌류우트-원호합성치형기어에 있어서 Hertz 식에 의하여 치면접촉응력을 구하고 유한요소법에 의하여 이뿌리응력을 계산하였다. 그리고 같은 제원의 표준 인벌류우트 치형기어와 비교하였다.

• 소성∙가공
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• 제24권3호
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• pp.212-217
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• 2015

SmartCrown is a system to control the plate crown by shifting the sine-shaped work rolls in the axial direction. The control range of the plate crown depends on a depth of sine-shaped roll profile because the roll radius varies continuously along the axial direction. When the roll profile is changed to improve the control range, the contact stress between the work roll and the back-up roll also changes. In the current study, the contact stress for various profiles and rolling conditions were analyzed using the finite element method and compared with results from Hertzian contact theory. A submodel method is used to increase the accuracy of the finite element analysis. The analysis results showed that the maximum increase in the contact stress was only 53MPa, so it is anticipated that no back-up roll spalling will occur.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.663-667
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• 2003

Mechanical force acted on the rail wheel causes excessive wear and increases the maintenance cost. The present paper proposes newly designed wheel profiles in order to reduce the contact stress. Numerical analysis on the stress distribution of wheel-rail contact stress is carried out using ABAQUS, a commercial finite element code. The result of KNR1/40 conical wheel is compared to those of the proposed wheels, all of which are arc wheel profile type.

• Journal of Advanced Marine Engineering and Technology
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• 제26권2호
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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.

• 대한기계학회논문집A
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• 제31권11호
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• pp.1083-1092
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• 2007

The objective of the present paper is to evaluate the effect of the evolution of contact surface profile caused by fretting wear on fatigue life of press-fitted shaft by means of an analytical method based on experimental data. A finite element analysis was performed to analyze the stress states of press-fitted shaft, considering the worn contact profiles of shaft. The fatigue lives of the press-fitted shaft reflecting the evolution of contact stress induced by fretting wear were evaluated by stress-life approach using fatigue notch factor. It is found that the stress concentration of contact edge in press-fitted shaft decreases rapidly at the initial stage of total fatigue life, and its location shifts from the contact edge to the inside with increasing number of fatigue cycles. Thus the change of crack nucleation position in press-fitted shaft is mainly caused by the stress change of contact edge due to the evolution of contact surface profile by fretting wear. Furthermore, the estimated fatigue lives by stress-life approach at the end of running-in period of the fretting wear process corresponded well to the experimental results. It is thus suggested that the effect of fretting wear on fatigue life in press fits is strongly related to the evolution of surface profile at the initial stage of total fatigue life.

• 한국철도학회논문집
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• 제10권5호
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• pp.546-553
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• 2007

본 연구는 압입축에 프레팅이 발생할 경우 프레팅 마모에 의한 접촉형상의 변화가 접촉응력의 분포, 균열발생 위치에 미치는 영향을 분석하고자 하였다. 압입축의 프레팅 피로실험시 측정한 접촉면의 프로파일을 이용하여 유한요소 해석을 수행하고 피로 사이클별 마모형상 변화에 따른 접촉면의 응력 변화를 분석하였다. 접촉면의 응력 해석결과를 이용하여 프레팅 피로손상 파라미터와 다축 피로이론를 적용하여 마모에 따른 균열발생위치의 변화를 해석하고 실험과 비교, 분석하였다. 프레팅 마모에 의해 접촉 끝단의 응력집중은 초기에 급격하게 감소하며, 마모가 진행될수록 응력집중의 위치는 접촉끝단에서 안쪽으로 이동한다. 따라서 프레팅 마모에 의한 접촉응력의 변화가 균열발생 위치의 변차와 다중균열발생의 주요원인임을 명확히 하였다.

• Tribology and Lubricants
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• 제15권2호
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• pp.164-170
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• 1999

Gerotor is widely used as a hydraulic pump or motor, by virtue of its volume changing ability. Performance deterioration of a gerotor hydraulic motor mainly due to the wear come from the contact between inner rotor with trochoidal curve and outer rotor with circular arc profile. This research covers the basic investigation about the contact forces of a gerotor hydraulic motor using analytic method. The influence of the eccentricity and the radius of circular arc teeth on the contact stress was evaluated.

• 대한기계학회논문집
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• 제10권6호
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• pp.870-875
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• 1986

본 연구에서는 랙의 이끝부분을 full-rounded tip으로 설계한 후, 이에 의하 여 창성되는 피니언의 이뿌리곡선을 구하여 전체치형을 완성하였다. 그리고 합성치 형기어의 미끄름율, 유효이뿌리원에서의 공칭굽힘응력과 두쌍접촉호의 길이대 원호부 분접촉호의 길이의 비인 접촉계수를 해석적인 방법으로 구하였다.또한 이들 특성들 과 물림율등 제특성을 비교.검토하여 공구압력각, 인벌류우트부분의 크기를 나타내는 물림각 및 원호반경등의 변화에 대한 제특성의 변화를 고려한 합성치형의 성능을 향상 시킬 수 있는 설계방법을 구하였으며, 합성치형과 표준인버류우트치형을 비교하였다.

• Tribology and Lubricants
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• 제5권2호
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• pp.107-112
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• 1989

This paper deals with strength analysis of tooth and method of manufacture of external tooth profile in harmonic drive. From the calculation of load imposed on the contact teeth, moximum contact stress is investigated to design the addendum modification coefficient. New tooth profile of the external gear is generated according to the law of gearing, assuming that internal gear has involute tooth profile. External tooth profile can't be manufactured by conventional exclusive tools which have pressure angle of 20$\circ$. The method to design cutter tooth profile is presented.