| During rail vehicle service life, wheel wear is an inevitable phenomenon with its increasing running mileage. Wheel wear will not only increase vehicle maintenance costs, but also change the wheel-rail compatibility including wheel-rail contact geometry and contact mechanics characteristics, which will impact vehicle dynamics performance. Severe wheel worn even results in serious train derailment or other accidents. With the continuous development of high-speed railway, heavy railway and urban rail transit, higher requirements for axle load and speed of the train are put forward, which are bound to exacerbate the wheel-rail interaction, as a result wear on wheel and rail profile become much severer. Therefore, investigation on wheel/rail wear has great significance both in theoretical value and in practical engineering application.The main research works in the present thesis are as follows:1) Literature reviews on present research on wheel wear were discussed in detail in terms of its research methods and achievement. The significance of wheel wear and current research direction were made clear.2) Field measurement on wheel-rail wear of a metro line was conducted to master the laws of the wheel-rail wear. Wheel wear was obvious in the investigated metro line. Wear on wheel flange wearwas severer than that on tread. Wear of outer rail in tight curve was apparent at rail gauge corner, while wear of inner rail was mainly on rail head.3) Influences of wheel wear on the wheel-rail contact geometry, contact mechanics and vehicle dynamics performace were analyzed in detail based on the corresponding simulations with the established vehicle dynamics model..4) The wheel wear prediction model consisted of four parts, including the vehicle system dynamics model established in a universal mechnism software packgae UM, wheel-rail local contact model, Archard material wear model and wheel profile smoothing and updating strategy. Simulation of wheel wear on a B-type metro vehicle was investigated. Results from simulation agreed well with the measurement results.5) Parameters influences on wheel wear were carried out based on the wheel wear prediction model. In the case of the same coefficient of friction of inner and outer rail surface, wheel wear increased with the increasing coefficient of friction. On the condition of ensuring traction and braking performance, the coefficient of friction should be controlled at around 0.3. Over-lubrication could reduce wheel wear, the wheel wear of non-lubrication (friction coefficient 0.4) wass smaller than that of the appropriate lubrication case. Suggestion was maked that using lubrication on the outer rail for the radius of curve less than 600 m, and coefficient of friction should be controlled at 0.15 to 0.2. For the curve with radius greater than 600 m, there was no need to use side-lubrication. Impact of rail inclination on wheel wear decreased with the increasement of curve radius. Rail inclination of 1/20 on the straight line and 1/40 on curve were recommended. Wheel wear on outer rail was greatly influenced by the superevelation, while it was less on inner rail. It was reconmened that the equilibrium speed should be set lower than vehicle speed in curve to reduce wheel wear. The longitudinal stiffness had great impact on the wheel wear, especially when negotiating curve. On the condition of ensuring the stability of the vehicle, the longitudinal stiffness should be about 7MN/m. |
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