Keywords: elastic sleeper, discrete element method, DEM, yade, track settlement, railway ballast, sleeper-ballast interaction, particle facet, pfacet, flexible sleeper, box test, cyclic loading.

Maintenance work on ballasted railway tracks due to the differential settlement along the track is a time-consuming and cost-intensive task. The mechanical properties of the sleeper, especially the sleeper’s bending behaviour under load, influence how the wheel-rail contact forces are transferred through the ballast bed to the ground, which in turn significantly affects track settlement. A deeper physical understanding on the interaction between the railway sleepers and the ballast can therefore help to improve railway infrastructure and reduce maintenance work. To study the dynamic sleeperballast interaction numerically the discrete element method (DEM) is a commonly used tool to get insight into the physical effects inside the ballast bed. However, in recent DEM related research the sleeper was rarely considered as an elastically deformable body and a simple yet accurate sleeper model that considers proper mechanical properties of the sleeper is still missing. Therefore, a model was developed that uses the particle facet model (PFM) to implement a sleeper with a smooth surface into the DEM framework without the need of time-consuming coupling methods. This approach enables railway track simulations that consider the effects of sleeper elasticity on the discrete ballast realistically. Box-test simulations were carried out, in which the elastic sleeper model was placed on a compacted ballast bed and then cyclically loaded. The results obtained from the simulations are in qualitative agreement with the literature. Additionally, it was shown that the simulation outcome heavily depends on the initial (filling) configuration of the ballast bed. The modelling approach offers a realistic integration of elastic sleepers into railway track DEM simulations and is able to provide deeper insights into the underlying physics of the sleeper-ballast interaction. Studies of complex railway track phenomena, like hanging sleeper situations, are thus made possible.

download the full-text of this paper (PDF, 9 pages, 353 Kb)

go to the previous paper
go to the next paper
return to the table of contents
return to the volume description