Vertical Vibration Characteristics of a Concrete Sleeper with Cracks in a Heavy-Haul Railway

With the continuous development of heavy-haul transportation, the dynamic interaction between heavy-haul train and track structure has dramatically intensified. Track structures bear repeated and huge loads over a long period of time, and concrete sleeper acting as an important load-bearing component inevitably generates various damages, in which transverse crack in the middle cross section of the sleeper occupies a large proportion. On the basis of the theory of linear elastic fracture mechanics, the concrete sleeper model is established through finite element method to analysis vertical vibration characteristic of damaged concrete sleeper under train loads, including the rail-sleeper forces calculated by vehicle-track coupled dynamics theory. Then stress intensity factor is introduced as an index to investigate the propagation of the transverse crack. The results show as follows: the modal frequencies of damaged concrete sleeper reduce to some extent; under train load, vertical acceleration and displacement of damaged concrete sleeper rise evidently; dynamic response of stress intensity factor in the crack tip shows that the intensity of stress field near the crack tip is controlled by Stress Intensity Factor Type-I.