| The development of high-speed rail undoubtedly brings convenience to our lives, but the higher speed of trains and the worse using conditions of train parts demand higher reliability and security of the train. Inspection and repair limit is the main basis that determines the timing of component overhaul. Scientific and rational locomotive repair limit can not only ensure EMU in good technical condition, but also can save costs. The wheel is a key component of running gear that ensure an EMU operate safe, so its strength and durability are put forward higher requirements. When vehicle operates, with the wheel having wear and damnation, we must repair wheels, so we must turn wheel repair in order to restore the wheel profile, but the diameter of wheel will become smaller. Explore the feasibility of further reducing the wheel diameter limit by theoretical analyzing and determine the maximum wheel diameter limit, which is significant to increased wheel life, improve the use of wheels and the current CRH2maintenance system optimization.In this dissertation, high-speed multiple units of CRH2is chosen as the research subject. A three-dimensional solid model of the wheel is built by CAD, Pro E and is meshed by Hypermesh. It is fainted element analysis by the software of ANSYS based on three conditions of UIC510-5standard.This paper studies the influence of structural strength when wheel diameter changes from the maximum stress endured by wheel and the stress of the inside and outside cross-section.Wheel fatigue strength were compared with two methods of fatigue analysis under key parts and the whole structure. We can find the weak wheel fatigue strength weak parts and explore the influence given wheel diameter change on fatigue strength of wheels same site through calculating fatigue strength of different diameter wheels so that we can provide a theoretical basis for determining the minimum wheel diameter limits.Due to the force loading of UIC standards can not evaluate the rim intensity evaluation, the wheel at different contact state and a different wheel diameter were analyzed by the wheel-rail contact theory and study on stress variation of the wheel rim in the wheel-rail contact state.Finally, from the viewpoint of structural strength and fatigue strength point of view, the minimum diameter limit for wheels is put forward new values. According to the theoretical analysis the wheel of the diameter were analyzed to verify. Studies have shown that the structural strength and fatigue strength of the wheel meet the requirements of safe operation of trains. Finally, through analyzing and comparing the results of this article, the wheel shape is recommended for improvement to ensure security and reliability of maximum wheel diameter limit.This article has some reference significance for wheel strength and limit research of CRH2EMU. Research results provide some theoretical basis for the high-speed train wheel structure design, extending wheel life and other aspects. At the same time, it has a certain reference value to further improve the CRH2maintenance. |
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