Slab track optimisation considering dynamic train–track interaction
Doctoral thesis, 2021
To this end, both two-dimensional (2D) and three-dimensional (3D) slab track models, and a transition zone model between slab track and ballasted track, have been developed. These models are used to simulate the vertical dynamic vehicle–track interaction in the time-domain. The computational cost of the simulation is reduced by using a complex-valued modal superposition technique for the finite element model of the track. In the 3D model, both rails are represented by beam elements, while the concrete parts are described using shell or solid elements. The simulations employ a mix of in-house and commercial codes. The influence of different irregularities, e.g. variations in track support conditions and irregularities in longitudinal level, on significant track responses such as wheel–rail contact forces, stresses in the concrete parts and pressure on the foundation is assessed. From Single-Input-Multiple-Output (SIMO) measurements carried out in a full-scale test rig, the 3D model has been calibrated and validated.
The developed models have been used to improve the designs of slab track and transition zones. Based on a multi-objective optimisation problem that is solved using a genetic algorithm, the transition zone design has been optimised to minimise the dynamic loads generated due to the stiffness gradient between the two track forms. The slab track design has been optimised to minimise the environmental footprint considering the constraint that the design must pass the static design criteria described in EN 16432-2. This design is then employed in the dynamic model where it is shown that there is a further potential for design improvements and related CO2 savings. In particular, there may be possibilities to reduce the thickness of the concrete layers and the amount of concrete between the rails. Finally, a model of reinforced concrete has been implemented and combined with the dynamic model to assess consequences of cracking in the concrete panel and to evaluate stresses in the reinforcement bars.
Dynamic vehicle–track interaction
Chalmers, Mechanics and Maritime Sciences (M2), Dynamics
Simulation of vertical dynamic vehicle–track interaction using a two-dimensional slab track model
Vehicle System Dynamics,; Vol. 56(2018)p. 1633-1657
Multi-objective optimisation of transition zones between slab track and ballasted track using a genetic algorithm
Journal of Sound and Vibration,; Vol. 446(2019)p. 91-112
Simulation of vertical dynamic vehicle–track interaction using a three-dimensional slab track model
Engineering Structures,; Vol. 222(2020)
Calibration and validation of the dynamic response of two slab track models using data from a full-scale test rig
Engineering Structures,; Vol. 234(2021)
Optimisation of slab track design considering dynamic train–track interaction and environmental impact
Engineering Structures,; Vol. 254(2022)
Slab tracks generally have low maintenance demands. However, if maintenance is required it may be expensive and intrusive. On the other hand, overdimensioning of slab track will lead to high environmental impact and monetary cost. In this thesis, computer models of slab tracks have been developed to fit test results. These models are used to increase the understanding of the impact of different operational conditions and track designs. Finally, the models are used in optimisations to strike the delicate balance between having a high-quality track and the environmental costs of having an overdesigned solution.
Research into enhanced track and switch and crossing system 2 (In2Track-2)
Swedish Transport Administration, 2018-11-01 -- 2021-10-31.
European Commission (EC) (EC/H2020/826255), 2018-11-01 -- 2021-10-31.
Design criteria for slab track structures (CHARMEC TS19)
Swedish Transport Administration, 2016-07-01 -- 2018-12-31.
Chalmers Railway Mechanics (CHARMEC) (CHARMEC TS19), 2019-01-01 -- 2021-06-30.
Areas of Advance
C3SE (Chalmers Centre for Computational Science and Engineering)
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4921
Opponent: Professor Ernesto García Vadillo, Department of Mechanical Engineering, University of the Basque Country, Bilbao, Spain