Effect of track irregularity on the dynamic response of a slab track under a high-speed train based on the composite track element method

• A vehicle/slab track interaction model is developed.
• A composite track element is presented to rapidly model the slab track.
• A finite element model of the slab track in high-speed railway is quickly proposed.
• The dynamic behaviours of the slab track are investigated.
• The effects of vehicle velocity on the dynamic responses are discussed.

Slab tracks are common track structures in high-speed railways. In this study, a vehicle/slab track interaction model is developed based on vehicle–track coupling dynamics theory, and composite track elements are used to rapidly model the finite element equations of the slab track based on the stationary value theory of total potential energy. In the model, the rail is represented as a discretely-supported infinite beam, the slab and the base are considered as continuously-supported free beams, and the connections of the track structure are modelled as viscoelastic spring–damping elements. The composite track element method effectively derives the equations of motion with high or low degrees of freedom by increasing or decreasing the number of track elements; therefore, it can be applied to the dynamic analysis of the track and to investigate the dynamic responses of the slab track system, including the rail, pad, slab, Cement asphalt mortar (CA mortar) and base. The equations of motion of the vehicle system are also proposed using the finite element method. The vehicle system and the slab track system interact through the vertical wheel/rail force, which is approximated using Hertz contact theory. The dynamic responses of a slab track subjected to moving vehicle loads are analysed using dynamic simulations and are compared with another classic simulation method. The effects of random track irregularity and vehicle velocity on the dynamic responses of the slab track system are discussed.

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