High-speed train gearbox housing vibration test based on small roller high-frequency excitation

To analyze the vibration characteristics and fatigue damage of a high-speed train gearbox housing, a small roller high-frequency excitation test stand was applied to study the vibration characteristics of gearbox housing under different vertical loads and speeds. In the test, the surface of roller was processed to the 13 th-order polygon with a radial jump amplitude of 0.05 mm, which could be equaled to a 20 th-order actual wheel polygon. The stress accumulation damage of gearbox housing per unit time was analyzed by the rain flow counting method and Miner linear damage rule. Analysis result indicates that effected by the resonance of the gearbox housing, the root mean square(RMS) values of transverse and vertical accelerations of each measuring point of the gearbox housing are minimal under different vertical loads and speeds at a running speed of the high-speed train of 200 km·h^-1. The RMS values of transverse and vertical accelerations of most measurement points are maximal when the vertical load is 23 t. The resonance of gearbox at the natural frequency of 573 Hz can be stimulated by the resonance frequency of test bench at a test speed of 100 km·h^-1 and main excitation frequency of the 20 th-order wheel polygon frequency shift of approximately 580 Hz at a test speed of 300 km·h^-1. The cumulative stress damage per unit time at each measuring point of gearbox housing largely fluctuates when the initial speed of wheel is between the speed grades of acceleration from 0 to 200 km·h^-1 and deceleration from 300 to 0 km·h^-1. The stress cumulative damage per unit time of each measuring point in the other speed grades has small fluctuations. The maximum value of stress damage per unit time is obtained in the tooth surface observation hole of a large gearbox housing, 3.72×10^-10, while the minimum damage is located above the bearing of a small gearbox housing, only 8.29×10^-18. Thus, the vibration acceleration of gearbox housing is largely affected by the resonance of gearbox and the deceleration operation and speed grades of test stand. However, the vertical load has a small influence on the stress cumulative damage per unit time under the conditions of non-resonance of gearbox housing, without deceleration operation, and the same speed grade of test stand.