Abstract
Severe short-pitch rail corrugation was found to have occurred on four types of track on the same metro line. Field investigations found that, even with the same operation conditions, the corrugations had different wavelengths for the different types of track. Impact hammer tap tests were conducted to investigate the dynamic behaviour of the tracks. The test results showed that, in the investigated metro, short-pitch corrugations are associated with the resonance behaviour of the tracks. The test results also showed that the corrugations on the investigated tracks are not caused by torsional vibration due to the wheelsets. Numerical simulations were conducted to identify the resonance behaviour that is could not be observed in the impact hammer tests due to the limitations in the test method. Three-dimensional finite element models for the four types of track were established and they were used to study the dynamic characteristics of the different tracks. The resonance frequencies and modes that are related to the generation of the corrugation were clearly identified in the numerical modelling studies; this further verifies the relationship between the formation of corrugation and the resonance behaviour of the tracks. The effect of a low value of the fastener stiffness on the dissipation of wheel/rail vibration energy was investigated with the help of numerical simulations. Both experimental and numerical results showed that the resonance behaviour of track structures is of great importance in determining the initiation, characteristics and development of the short-pitch corrugation on the investigated tracks.
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