Efficient DEM simulations of railway ballast using simple particle shapes
1Virtual Vehicle Research GmbH, Inffeldgasse 21/A, A-8010, Graz, Austria.
Granular Matter
|September 19, 2022
Summary
This study introduces efficient discrete element method (DEM) models for railway ballast using simple particle shapes and advanced contact laws. These models achieve accurate simulations by incorporating physical effects like edge breakage.
Area of Science:
- Geotechnical Engineering
- Computational Mechanics
- Material Science
Background:
- Discrete Element Method (DEM) models for complex materials like railway ballast often face a trade-off between computational efficiency and simulation accuracy.
- Existing DEM models for railway ballast typically employ complex particle shapes with simplified contact laws, leading to high computational costs.
- There is a need for DEM models that are both computationally efficient and accurately represent the behavior of railway ballast.
Purpose of the Study:
- To develop efficient and accurate DEM models for simulating railway ballast behavior.
- To investigate the suitability of simple particle shapes (clumps of spheres) in DEM simulations of railway ballast.
- To establish a relationship between particle shape descriptors and their performance in DEM models.
Main Methods:
- Constructed simple particle shapes (clumps of three spheres) based on shape analysis of real ballast.
- Developed and parameterized a DEM contact law incorporating additional physical effects, such as edge breakage.
- Performed DEM simulations of compression and direct shear tests using the parameterized shapes and contact law.
- Conducted micromechanical analysis of the best-performing particle shapes.
Main Results:
- Accurate DEM simulation results were achieved by combining simple particle shapes with a contact law that includes physical effects like edge breakage.
- The most suitable particle shapes for DEM modeling of railway ballast were identified as non-overlapping spheres with high interlocking potential, low sphericity, and high convexity.
- Micromechanical analysis revealed that three out of the four best-performing shapes exhibit similar bulk and micro-scale behavior, while one shape showed distinct micro-scale characteristics.
Conclusions:
- The proposed approach of using simple particle shapes with advanced contact laws offers a pathway to achieve both computational efficiency and accuracy in DEM modeling of railway ballast.
- The study provides insights into selecting appropriate particle shapes for DEM simulations based on their descriptors and expected performance across different load cases.
- This work represents a significant step towards more efficient and accurate DEM simulations for railway track infrastructure.
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