• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(I)
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• pp.204-209
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• 2003

The railway vehicle is composed of many suspension components, such as 1st springs, 2nd dampers, that have an influence on the dynamic characteristics of high speed train. Also, the wheel/rail shapes and its contact mechanism affect the dynamic behavior of high speed train. but these geometric contact characteristics are nonlinear functions of the wheelset lateral displacement and it do not exact dynamic analysis for high speed train. there is a need to develop a new wheel/rail contact module for dynamic behavior and wheelset model is divided motor box, wheel box and wheel body. This wheel is moved by motor box and constrained by joint. It is almost same a train and its result is more exactly.

• 한국안전학회지
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• 제26권3호
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• pp.1-7
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• 2011

Fatigue damage on the train wheel surface was estimated by considering the effect of friction coefficient of rolling on the contact surface between the wheel and rail during operation. From FEM analys, the maximum Tresca stress was 550.7 MPa at a depth of 2.07 mm under the maximum contact pressure ($P_{max}$ = 894.3 MPa) between wheel and rail. The maximum stress continued to increase along with the increase in the frictional coefficient. The fatigue initiation lifetime of the wheel by the rolling contact was predicted using the Smith-Watson-Topper (SWT) equation and the maximum principal strain equation (${\varepsilon}$-N).

• 대한기계학회논문집A
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• 제29권10호
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• pp.1384-1391
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• 2005

Damage often occurs on the surface of railway wheels due to wheel-rail contact fatigue. It should be removed before reaching wheel failure, because wheel failure can cause derailment with loss of life and property. The increase or decrease of the contact fatigue lift by the metal removal of the contact surface were investigated by many researchers, but they have not considered initial residual stress and traction force. The railway wheel has the initial residual stress formed during the manufacturing process, and the residual stress is changed by thermal stress induced by braking. The traction force and residual stress are operated on wheels of locomotive and electric motor vehicle. In this study, the effect of metal removal depth on the contact fatigue life for a railway wheel has been evaluated by applying lolling contact fatigue test. The effect of the traction force and metal removal on the contact fatigue life has been estimated by finite element analysis. It has been found that the initial residual stress determines the amount of metal removal depth if the traction coefficient is less than 0.15. If the traction coefficient is greater than 0.2, however, the amount of metal removal depth is independent on the intial residual stress.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.714-719
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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 wheel/set life and safety has been requested. One of the major reasons of railway wheel damage is a contact zone failure by wheel/rail contact. In this paper, we conducted a rolling contact fatigue test for wheels using a specimen of wheel/rail. the behavior of hardeness and residual stress below the contact surface of the test pieces in the fatigue process were analyzed. Finally, the relation between fatigue life and contact pressure was obtained.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.18-24
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• 2010

철도차량의 동특성 해석을 위한 기존의 연구는 대부분 2차원 접촉해석에 근거한 근사해법에 의존해 왔다. 최근에 휠-접촉해석에 대한 정확한 해를 구하기 위해 3차원적 접근방법이 제시되고 있지만, 계산시간의 과다로 인해 실제 시뮬레이션 적용에는 효과적이지 못했다. 본 연구의 주요 관점은 효율적인 3차원 휠-레일 접촉 해석을 통해 휠-레일 접촉력을 계산하여 철도차량의 동특성 해석의 새로운 방법을 제시하고자 하는 것이다. 이를 통해, 3차원 휠-레일 접촉해석 및 휠셋의 동적 계산식이 제시된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.692-697
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• 2004

Damage often occurs on the surface of railway wheel by wheel-rail contact fatigue. It should be removed before reaching wheel failure, because wheel failure can cause derailment with loss of life and property. The increase or decrease of the contact fatigue life by the metal removal of the contact surface were shown by many researchers, but it has not explained precisely why fatigue life increases or decreases. In this study, the effect of metal removal depth on the contact fatigue life for railway wheel has been evaluated by applying finite element analysis. It has been revealed that the residual stress and the plastic flow are the main factors determining the fatigue life. Finally, the contact fatigue life according to metal removal has been estimated.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1238-1245
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• 2000

One of the main causes of severe wear or crack initiation in wheel and rail is the contact stress due to wheel-rail contact. First, we obtain contact stress due to the rail mounting slope using the finite element method. Second, the shape design based on more reasonable contact stress analysis rather th~n a general Hertzian contact theory is investigated in order to reduce the contact stress. The optimum -design is performed using the simple 2-D finite element model and its results are verified by 311) finite element analysis.

• 한국철도학회논문집
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• 제11권6호
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• pp.524-529
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• 2008

도시철도 차륜에서 손상된 차륜은 주행 중의 승차감 악화 및 보수비용의 증가로 이어질 수 있기 때문에 차륜답면 특성 변화에 대한 평가는 대단히 중요하다. 본 연구에서는 비파괴적 표면검사법을 이용하여 차륜답면의 손상 평가를 실시하였으며 접촉위치, 주행거리, 제동방식에 따라 차륜답면의 특성을 평가하였다. 그 결과 접촉위치에 따라 차륜답면이 현저히 다른 손상 특성을 나타남을 보여주고 있다.

• 소음진동
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• 제8권4호
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• pp.616-622
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• 1998

An analytical method has been developed to estimate the dynamic contact force between wheel and rail when trains are running on rail with vertical irregularities. In this method, the effect of Hertzian deformation at the contact point is considered as a linearized spring and the wheel is considered as an sprung mass. The rail is modelled as a discretely-supported Timoshenko beam, and the periodic structure theory was adopted to obtain the driving-point receptance. As an example, the dynamic contact force for a typical wheel/rail system was analysed by the method developed in this research and the dynamic characteristics of the system was also discussed. It is revealed that discretely-supported Timoshenko beam model should be used instead of the previously used continuously-supported model or discretelysupported Euler beam model, for the frequency range above several hundred hertz.

• 한국자동차공학회논문집
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• 제16권3호
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• pp.137-143
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• 2008

For most bearings, it is a common requirement to have long durability. Especially wheel bearing fatigue life is the most important in automotive quality. The contact fatigue life analysis of automotive wheel bearing considering real raceway rough surface is presented in this paper. Contact stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions; the subsurface stress field is obtained using rectangular patch solutions. Mesoscopic multiaxial fatigue criterion which can yield satisfactory results for non-proportional loading is then applied to predict fatigue damage. Suitable counting method and damage rule were used to calculate the fatigue life of random loading caused by rough surface. The life analysis considering real rough surface of wheel bearing raceway is in good agreement with the experimental results.