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Discrete element technique for modeling high-speed railway tracks

Time: Tue 2023-05-30 10.00

Location: B3, Brinellvägen 23, Stockholm

Video link:

Language: English

Subject area: Civil and Architectural Engineering, Soil and Rock Mechanics

Doctoral student: Alireza Ahmadi , Jord- och bergmekanik

Opponent: Associate Professor Liang Cui, University of Surrey

Supervisor: Professor Stefan Larsson, Jord- och bergmekanik; Dr. Carl Wersäll, Jord- och bergmekanik

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QC 230508


The Discrete element method (DEM) is a methodology to investigatethe interactions among granular materials. It analyzes the behavior of par-ticulate environments by solving force-displacement equations that adhereto Newton’s second law of motion. Despite its usefulness, the DEM is notwithout limitations, and researchers are still facing certain challenges thatrestrict them from performing detailed analyses of granular materials. Thisstudy addresses two issues in DEM modeling of granular materials in rail-way embankments. Firstly, the long computational time required by theDEM for modeling fine angular particles in granular materials is addressedby exploring the effects of particle scaling on the shear behavior of granularmaterial. This study investigates the impact of particle size distribution,particle angularity, and the amount of scaling on the accuracy and compu-tational efficiency of DEM. Secondly, the limitations of DEM in includingthe continuous rail beam structure in the track are addressed by verifyinga DEM model against physical measurements of a full-scale ballasted trackand investigating the influence of including the rail beam structure on high-speed railway ballasted tracks. The results show that the use of particlescaling in the first study significantly improves the computational efficiencyof the DEM while maintaining accuracy, and this method is used in thesecond study to investigate the influence of the rail beam structure on thebehavior of railway tracks.