Mechanical Characteristics of Low-Wind-Pressure Catenary Positive Feeder in Gale Area of Lanzhou‒Urumuqi High-Speed Railway

In order to restrain the galloping amplitude of the positive feeder in the gale area of the Lanzhou‒Urumuqi high-speed railway and ensure the safe operation of the train, firstly, a novel type of low-wind-pressure catenary positive feeder was designed, and the aerodynamic parameters and galloping amplitude of the conventional catenary positive feeder and the low-wind-pressure catenary positive feeder under different wind loads were simulated and compared. Then, a three-dimensional finite element model of the low-wind-pressure catenary positive feeders with the three better anti-galloping effects was established and tensile loads were applied to simulate the stress condition of the positive feeder when the positive feeders were galloping. Finally, the deformation and variation stress of the low-wind-pressure catenary positive feeder were analyzed. The results show that, the deformation of the free end of the catenary positive feeder is much larger than that of the fixed end, the deformation of the aluminum strand layer is larger than that of the steel strand layer, and the further to the outer layer, the larger the strand deformation, twining alternately steel and aluminum layers can be considered in the feeder manufacturing to balance the electroconductibility and rigidity. The stress concentration occurs at the location where the strands squeezing with each other, and the stress concentration position is the same as the direction of the strand twining with each other. A buffer layer should be considered on the surface of the strands during the positive feeder manufacturing, to mitigate oscillatory shock between the strands when the positive feeder galloping, and to prolong the service life of the positive feeder. The larger the ratio of the groove radius of the low-wind-pressure catenary positive feeder to the radius of the conventional feeder, the greater the deformation of the outermost aluminum strands, the strands are more likely to break when the positive feeder is galloping. Therefore, the type selection of low wind pressure positive feeder should be comprehensively considered to balance the anti-galloping effectiveness and the service life.