Influence of temperature gradient of slab track on the dynamic responses of the train-CRTS III slab track on subgrade nonlinear coupled system

Temperature is an important load for ballastless track. However, there is little research on the system dynamic responses when a train travels on a ballastless track under the temperature gradient of ballastless track. Considering the moving train, temperature gradient of slab track, gravity of slab track, and the contact nonlinearity between interfaces of slab track, a dynamic model for a high-speed train runs along the CRTS III slab track on subgrade is developed by a nonlinear coupled way in ANSYS. The system dynamic responses under the temperature gradient of slab track with different amplitudes are theoretically investigated with the model. The results show that: (1) The proportions of the initial force and stress caused by the temperature gradient of slab track are different for different calculation items. The initial fastener tension force and positive slab bending stress have large proportions exceeding 50%. (2) The maximum dynamic responses for slab track are not uniform along the track. The maximum slab bending stress, slab acceleration, concrete base acceleration appear in the slab middle, at the slab end, and at the concrete base end, respectively. (3) The maximum accelerations of track components appear when the fifth or sixth wheel passes the measuring point, and at least two cars should be used. (4) The temperature gradient of slab track has a small influence on the car body acceleration. However, the influences on the slab acceleration, concrete base acceleration, fastener tension force are large, and the influence on the slab bending stress is huge.