Thermal analysis and temperature characteristics of a braking resistor for high-speed trains for changes in the braking current

Abstract This paper establishes a dynamics model of the axle box bearing of high-speed trains. The model can obtain contact force and its change law. Between rollers and raceway when the bearing contains outer ring faults, inner ring faults, and rolling element faults. Based on the model, the thermal network method is introduced to study the temperature characteristics of axle box bearings of high-speed trains. In this model, the bearing can be divided into some isothermal nodes. The heat generation, conduction, and dispersion of these isothermal nodes can be solved. The results show that the temperature of the contact point between the outer ring raceway and the rolling elements is the highest. By analyzing the relationship between the node and the speed and fault size, it is obtained that the higher the speed, the higher the node temperature. When the fault size increases, the node temperature first increases and then decreases.

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Experimental research into the low-temperature characteristics of a hydraulic damper and the effect on the dynamics of the pantograph of a high-speed train running in extreme cold weather conditions

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409719879029 ◽

2019 ◽

Vol 234 (8) ◽

pp. 896-907

Author(s):

Wenlin Wang ◽

Yuwen Liang ◽

Weihua Zhang ◽

Simon Iwnicki

Keyword(s):

Low Temperature ◽

Experimental Research ◽

High Speed ◽

Weather Conditions ◽

Cold Weather ◽

Temperature Characteristics ◽

Hydraulic Damper ◽

Damping Characteristics ◽

High Speed Trains ◽

Extreme Cold

There is likely to be a demand to run high-speed trains in extreme cold weather conditions in the near future; therefore, it is important to study the change in the characteristics of the materials and components in an extreme cold environment and their effects on the vehicle system dynamics. Experimental research into the low temperature characteristics of a pantograph hydraulic damper was carried out in this study. The results show that low temperature causes an increase in damping forces, and when the temperature is above the boundary temperature range, most indices of the damping capability increase with the decrease of temperature; when the temperature is below the boundary temperature range, most indices decrease with the decrease of temperature. Key parameters are identified to obtain the theoretical description of low-temperature damping characteristics using a simplified-parametric damper model and the experimental data. A mathematical model of the pantograph–catenary system incorporating the pantograph damper model is then established to calculate the effect of the damper performance on the pantograph dynamics low temperatures. Simulation results show that the lowering performance of the pantograph deteriorates noticeably due to the unstable low-temperature damping characteristics, but the deterioration of the raising performance and contact quality of the pantograph due to the low-temperature characteristics of the damper are less obvious. The results obtained in this study are valuable for understanding the low-temperature characteristics of a hydraulic damper, and instructive in the optimal specification of the pantograph damper for high-speed trains running in cold weather conditions.

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