Effects of static and dynamic material properties on vibration responses of slab tracks in high speed railways

As an essential element for simulations, material properties of slab track components have significant influences on the coupling vibration responses of both high speed trains and tracks. In reality, the material properties of slab track components are different when they are determined by using either static or dynamic load tests. Based on a critical literature review, most previous studies adopted static material properties despite the fact that the actual loads from high speed trains onto slab tracks are dynamic excitation. This study is thus aimed at highlighting the influence of dynamic properties on the highspeed train-track interactions. In order to identify the differences of vibration responses of slab tracks under static and dynamic properties, a 3D coupled vehicle-slab track model has been built based on multi-body simulation principle and finite element method using LS-DYNA. The model has been validated by design values and a very good agreement is found. The strain rates of concrete and CA mortar have been evaluated firstly in order to determine their dynamic moduli of elasticity. The wheel-rail contact force, the vertical displacement of slab track, and the stress of slab track components have been simulated using both measured rail surface and perfect rail surface conditions when the two types of material properties were considered. And then the deviation of dynamic responses of slab tracks under different material properties has been obtained. The insight from this study provides a new reference and recommendation for adopting suitable and realistic material properties of high speed slab tracks in practice.