Endommagement par fatigue de contact d'une roue ferroviaire : étude numérique par éléments finis

Abstract : This study by finites elements proposes to estimate the Rolling Contact Fatigue (RCF) strength of a railway wheel. The first part of the thesis presents a critical analysis of the approaches of the literature relatives to the various aspects of the problem of RCF. The second part relates to the two-dimensional modeling of a railway wheel, consist a defect circular, and subjected to a moving hertzian contact pressure .The damage is quantified by a Fatigue Parameter (FP) based on the density of energy and the concept of critical plan. The lifetime is calculated using a law consist of the parameters of low-cycle fatigue. It is shown that the technique of the submodeling is an effective tool to reduce the computing time CPU. The third chapter is a parametric study about the influence over the lifetime, of the loading level, the defect depth, the nature and the size of the defects. The results show that the critical plan of crack initiation is parallel to the contact surface when mode I dominate; it deviates when mode II is dominating. The fourth chapter relates to the influence of the loadings with variable amplitudes and that of friction. We show the beneficial effect of an overload over the lifetime to crack initiation. The harmful incidence of the coefficient of friction over the lifetime is highlighted in the case of a wheel with and without defect. Finally, the last part of this work approaches the effects of inertia in the case of the RCF. The lifetime is over-estimated in the static case and decreases in dynamics with the rolling speed and the loading level
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Modar Taraf. Endommagement par fatigue de contact d'une roue ferroviaire : étude numérique par éléments finis. Autre [cond-mat.other]. Université Paul Verlaine - Metz, 2008. Français. ⟨NNT : 2008METZ021S⟩. ⟨tel-01752589⟩

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