Simple particle shapes for DEM simulations of railway ballast -- influence of shape descriptors on packing behaviour

Bettina Suhr*, Klaus Six

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In any DEM simulation, the chosen particle shape will greatly influence the simulated material behaviour. For a specific material, e.g. railway ballast, it remains an open question how to model the particle shape, such that DEM simulations are computationally efficient and simulation results are in good accordance with measurements. While DEM shape modelling for railway ballast is well addressed in the literature, approaches mainly aim at approximating the stones’ actual shape, resulting in rather complex and thus inefficient particle shapes. In contrast, very simple DEM shapes will be constructed, clumps of three spheres, which aim to approximate shape descriptors of the considered ballast material. In DEM simulations of the packing behaviour, a set of clump shapes is identified, which can pack at porosities observed at track sites, as well as in lab tests. The relation between particle shape (descriptors) and obtained packing (characteristic) is investigated in a correlation analysis. The simulated packing’s porosity is strongly correlated to four shape descriptors, which are also strongly correlated among each other. Thus, to derive simple shape models of a given particle shape, matching one of these shape descriptors, might be a good first step to bring simulated porosities closer to measured ones. The conducted correlation analysis also shows that packing’s coordination number and isotropic fabric are correlated to more shape descriptors, making it more difficult to estimate the effect of particle shape on these quantities
Original languageEnglish
Article number43
JournalGranular Matter
Issue number2
Publication statusPublished - 1 May 2020


  • DEM modelling
  • Efficiency
  • Packing behaviour
  • Particle shape
  • Railway ballast

ASJC Scopus subject areas

  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Materials Science(all)

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