This paper conducts a detailed investigation into the formation mechanism of wheel polygonalization in high-speed trains and its influence factors through numerical simulation. A finite element model including two rails, one wheelset, and three disc brake units is set up to study the formation mechanism of wheel polygonalization in high-speed trains based on the point of view of frictional self-excited vibration. Using the finite element complex analysis, the dynamic stability of the wheelset–track–disc brake system is studied. In addition, the influence factors on the wheel polygonalization are investigated. Results show that when the longitudinal creep force is unsaturated, the 21-order polygonal wear of wheels occurs easily due to the self-excited vibration of the disc brake unit. When the longitudinal creep force is saturated, the 12-order polygonal wear of wheels probably occurs due to the self-excited vibration of the disc brake unit. The bigger the friction coefficient between the brake disc and pad, the greater the occurrence propensity of the polygonal wear of wheels. Vertical fastener damping that is too large or too small is disadvantageous for suppressing wheel corrugation. However, increasing the lateral fastener damping is beneficial for reducing the polygonal wear of wheels. When the vertical fastener stiffness is 25 MN/m, 7-order, 9-order, and 14-order wheel polygonalization can easily occur. A higher lateral fastener stiffness is beneficial for the suppression of wheel polygonalization.

In Chinese metro lines, Vanguard fastener system is widely used as vibration damping fastener. However, the rails mounted with this fastener system are deeply affected by rail corrugation. The generation mechanism of corrugation wear at a metro track mounted with Vanguard fastening is revealed through the numerical simulation method. A finite element model including two rails, the track system, and a leading wheelset is set up. The parameter sensitivity analysis is conducted to identify the dominant factors affecting the rail corrugation. Then, the remedy method to suppress the corrugation wear is put forward on the basis of the parameter analysis results. The results indicate that the severe corrugation wear on the inner rail is attributed to the self-sustained vibration of the wheelset–track system aroused by the saturated wheel–rail creep force. The frequency of the rail corrugation calculated by the model is very close to the measured data. The elastic modulus and the damping coefficient of the rubber rest pad in the Vanguard fasteners have a high impact on rail corrugation. Increasing the elastic modulus and the damping coefficient can effectively restrain or even eliminate the rail corrugation. Bringing the damping coefficient of the rubber rest pad above 0.0001 can significantly alleviate the rail corrugation. The influence of the damping and stiffness of the rubber pad under the floating slab track bed is negligible.

Rail corrugation is very serious in Cologne egg fastener track; effective control measures are still lacking. The cause of the corrugation wear on a curved metro track is analyzed based on the friction-induced vibration theory. A finite element model is established to study the frequency domain and time domain features of the friction-induced oscillation of this system. The influences of the fastener spacing and the fastener support length on the corrugation wear are investigated to develop countermeasures. The simulation results show that the friction-induced vibration of the wheel-track system is the wavelength-fixed mechanism of the corrugation wear of rail of the curved Cologne egg fastener track. There are two reasons why the low rail corrugation wear is more serious. The contact resultant force between the low rail and the wheel is obviously bigger than that between the wheel and the high rail, resulting in a higher wear rate of the low rail. The contact force fluctuation of the low rail caused by the friction-induced vibration is more severe, resulting in a higher corrugation wear evolution speed on the low rail. The friction-induced oscillation cannot be eliminated only by adjusting the fastener support length and spacing. However, the long-wavelength corrugation wear instead of the more harmful short-wavelength corrugation wear can be produced by adjusting the fastener support length and the fastener spacing to alleviate the influence of corrugation wear on the vehicle-track system.

Corrugated wear on the metro curved track was studied. Dynamic analysis was implemented to analyze the effects of the vehicle speed and the curve radius on the wheel-rail creep forces. A mixed Lagrangian/Eulerian description-based finite element model of a wheel/rail system was set up. The wheel inertia can be considered in this model. Moreover, the steady rolling of the wheel under different creepage for braking or traction can be simulated. The complex eigenvalue analysis is used to investigate the frequency-domain characteristics of the friction-induced vibration of the wheel/rail system under the steady-state curving of the wheel. The initiation of the corrugation under the friction-induced vibration of the wheel/rail system was studied. The effects of the creep forces in the longitudinal and lateral directions on the friction-induced vibration of the wheel/rail system were revealed. The results show the dominant cause of the corrugation on the low rail surface is the friction-induced vibration of the wheel/rail system at about 320 Hz. The friction-induced vibration on the side of the high rail is not easy to occur. Therefore, the corrugated wear hardly happens to the high rail. The corrugated wear caused by the friction-induced vibration is frequency-fixed. It is necessary to consider the wheel inertia in the study of the friction-induced vibration of the wheel/rail system. Without considering wheel inertia, missing prediction of the friction-induced vibration and overestimation of the occurrence probability and development speed of the corrugation may occur. The lateral creep force plays a leading role in the friction-induced vibration of the wheel/rail system, while the longitudinal creep force has little effect on the friction-induced vibration. The corrugated wear will become more serious as the curve radius becomes smaller.

In response to vibration problems caused by unbalanced faults in multi-disk rotor systems of compressors, this research study proposes a new type of integral damping bearing (IDB) with an integral structure and better damping performance. The IDB’s stiffness and damping coefficients were acquired through computational fluid dynamics (CFD) analysis. When the IDB was applied to a multi-disk rotor system, the analysis results show that it effectively lowered the bending stress and strain energy of the shaft and enhanced the stability of the system. The bending stress was reduced from 45 MPa (with traditional ball bearings) to 8.63 MPa (with the IDB). By using the IDB, the strain energy borne by the shaft and bearing was only 10.44%. Subsequently, experimental research was conducted on the suppression of unbalanced vibration by using the IDB under various working conditions. The peak amplitude of the rotor system with the IDB was reduced by 19.94%, and the amplitude at the 1X frequency was reduced by 32.73% compared with ball bearings. The experimental results indicate that the IDB can efficiently dampen the vibration of the rotor system. And it was found that the IDB has stable vibration reduction performance under various working conditions.