Effect of axle box rotary arm node performance on wheel-rail coupling vibration for high-speed EMUs

To analyze the effect of axle box rotary arm node performance on the wheel-rail coupling vibration under wheel-rail short-wave irregularities such as rail corrugation and wheel polygon, the comprehensive research was conducted from three aspects, such as simulation calculation, field test, and bench test. A dynamics simulation model of a vehicle-track rigid-flexible coupling system was established to analyze the effects of rail corrugation and wheel polygon on the wheel-rail coupling vibration. The effects of new and old axle box rotary arm nodes on the axle box vibration responses under the rail corrugation and the bogie vibration responses under the high-order polygon were tested using a rolling test bench along the Wuhan-Guangzhou High-Speed Railway Line. 10 million fatigue durability tests were conducted on the type A and B axle box rotary arm nodes that have been in service for 1.2 million km, to demonstrate the fatigue reliability safety margins of the nodes. Research results show that the vibration accelerations of rails and axle box as well as the wheel-rail vertical force effectively remain unchanged with an increase in the radial stiffness of the axle box rotary arm node from 40 MN·m^-1 to 200 MN·m^-1, when the rail wavelength is 120 mm, the wheel polygon is of the 20th order, and the wave depths of rail corrugation and wheel polygon are both 0.04 mm. The change in the axle box rotary arm node stiffness will not significantly influence the wheel-rail coupling vibration responses under short-wave excitations such as rail corrugation and wheel polygon. With an increase in the number of fatigue test, the radial and axial stiffnesses of axle box rotary arm nodes decrease gradually. After 10 million fatigue durability tests, the appearances of the decommissioned axle box rotary arm nodes remain basically unchanged. Although the core shaft and rubber adhesive parts show slight tackle and cracking, the tackle and cracking depths are not more than 5 mm. The rubber body itself shows no cracks. In general, the performance still meets the General Technical Requirements for Rolling Stock Rubber to Metal Parts (TB/T 2843—2015). 3 tabs, 14 figs, 30 refs.