Cavitation induced hydraulic yaw damper failure and its effect on railway vehicle dynamic stability

Abstract

Hydraulic yaw damper (HYD) is an important suspension component that ensures the safe and stable operation of high-speed railway vehicles. However, HYD experiences the performance degradation and failure during service. Recent research found that the cavitation in HYD can affect vehicle stability by deteriorating the dynamics performance of HYD. To reveal the influence mechanism and quantify the effect extent of cavitation on hunting stability, this study delves into the cavitation phenomenon in HYD through theoretical modeling, numerical simulation and experimental validation. Considering the gas phase composition in hydraulic oil and the dynamic process of each phase transformation, a multi-phase interaction dynamic model of the hydraulic oil was originally proposed. Based on this sub-model, the physical parametric model of the HYD was established and integrated into the vehicle system as an advanced force element to study the effect of cavitation on vehicle hunting stability. The results indicate that cavitation can lead to insufficient damping force in the extension or compression stroke of HYD, subsequently affecting the vehicle hunting stability. Comparing the effects of different initial gas content on bifurcation characteristics and hunting frequency, it is observed that an increase in initial gas content results in a decrease in both linear and nonlinear critical speeds, changes in the bifurcation type and an increase in the hunting frequency. Furthermore, this effect is nonlinear, exhibiting sensitive ranges and saturation values. To ensure operational stability of high-speed vehicles, measures should be taken to prevent cavitation in HYD.