Thermal Modelling and Experimental Comparison for a Moving Pantograph Strip
This paper proposes a thermal study of the catenary/pantograph interface for a train in motion. A 2.5D complex model of the pantograph strip has been defined and created by a coupling between a 1D and a 2D model. Experimental and simulation results are presented and with a comparison allow validating the 2.5D model. Some physical phenomena are described and presented with the help of the model such as the stagger motion thermal effect, particular heats and the effect of the material characteristics. Finally it is possible to predict the critical thermal
configuration during a train trip.
Wear Properties of Metal-Impregnated Carbon Fiber-Reinforced Carbon Composite Sliding Against a Copper Plate Under an Electric Current
The metal-impregnated carbon fiber-reinforced carbon composite (C/C composite) is expected to be a candidate material for pantograph contact strips of high-speed electric railway vehicles, because its mechanical strength for flexure and impact is much higher than that of the conventional metal-impregnated carbon. The authors have investigated the wear properties of copper-titanium-alloy impregnated C/C composite sliding against a copper disk under an electric current and frequent arc discharges. The tested C/C composite was prepared by press molding and baking of laminated carbon fiber woven sheets. There exists anisotropy in the physical properties originated from the orientation of carbon fiber woven sheets lamination. The C/C composite was slid in two directions, in parallel with or perpendicular to the sheet layer. The test results show that the wear rate in sliding in the parallel direction exceeds that in the perpendicular direction, especially in the cases where the material is subjected to higher current density and more frequent arc discharges.Copyright © 2005 by ASME
Effect of Alloying Elements on Thermal Wear of Cast Hot-Forging Die Steels
The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wear of cast hot-forging die steels. The wear rates decrease with an increase in chromium content from 3% to 4% and molybdenum content from 2 % to 3 %, respectively. With further increase of chromium and molybdenum contents, chromium slightly reduces the wear resistance and molybdenum severely deteriorates the wear resistance with high wear rate. Lower vanadium/carbon ratio (1. 5–2. 5) leads to a lower wear resistance with higher wear rate. With an increase in vanadium/carbon ratio, the wear resistance of the cast steel substantially increases. When vanadium/cartion ratio is 3, the wear rate reaches the lowest value. The predominant mechanism of thermal wear of cast hot-forging die steels are oxidation wear and fatigue delamination. The Fe2O3 and Fe3O4 or lumps of brittle wear debris are formed on the wear surface.