A NEW MECHANISM FOR SQUEALING NOISE AND FRICTION-INDUCED VIBRATIONS IN THE RAILWAY INDUSTRY

In the paper, a new mechanism for squealing vibration based on the time delay concept of friction is introduced. Firstly, several test results on the time delay between the varying normal force and the consequent varying friction are presented and discussed. Secondly, the motion stability of a friction system with the time delay is analyzed in theory. The result shows that the friction system may become unstable in the presence of the time delay. Thirdly, the advantages and disadvantage of the new mechanism are discussed. The remaining part of the paper will present several research advances in the application of friction-induced vibration theory in the railway industry. In the authors' work, a finite element model of friction self-excited vibration of a railway wheelset-track system is established. The motion stability of the model is analyzed. Numerical results show that friction between the wheel and rail easily causes self-excited vibration of a railway wheelset-track system. The relation between the rail corrugation and friction-induced vibration is discussed. Finally, the field test results in Subway line 4 of Beijing are presented. The test results show that there exists self-excited vibration of a railway wheelset-track system when vehicles negotiate sharp curved tracks.