Mechanisms of Adhesion Increase in Wet Sanded Wheel–Rail Contacts—A DEM-Based Analysis
In railways, problems in braking and traction can be caused by so-called low-adhesion conditions. Adhesion is increased by sanding, where sand grains are blasted towards the wheel–rail contact. Despite the successful use of sanding in practice and extensive experimental studies, the physical mechani...
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MDPI AG
2025-07-01
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| Series: | Lubricants |
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| Online Access: | https://www.mdpi.com/2075-4442/13/7/314 |
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| author | Bettina Suhr William A. Skipper Roger Lewis Klaus Six |
| author_facet | Bettina Suhr William A. Skipper Roger Lewis Klaus Six |
| author_sort | Bettina Suhr |
| collection | DOAJ |
| description | In railways, problems in braking and traction can be caused by so-called low-adhesion conditions. Adhesion is increased by sanding, where sand grains are blasted towards the wheel–rail contact. Despite the successful use of sanding in practice and extensive experimental studies, the physical mechanisms of adhesion increase are poorly understood. This study combines experimental work with a DEM model to aim at a deeper understanding of adhesion increase during sanding. The experimentally observed processes during sanding involve repeated grain breakage, varying sand fragment spread, formation of clusters of crushed sand powders, plastic deformation of the steel surfaces due to the high load applied and shearing of the compressed sand fragments. The developed DEM model includes all these processes. Two types of rail sand are analysed, which differ in adhesion increase in High-Pressure Torsion tests under wet contact conditions. This study shows that higher adhesion is achieved when a larger proportion of the normal load is transferred through sand–steel contacts. This is strongly influenced by the coefficient of friction between sand and steel. Adhesion is higher for larger sand grains, higher sand fragment spread, and higher steel hardness, resulting in less indentation, all leading to larger areas covered by sand. |
| format | Article |
| id | doaj-art-2ad7cb9efbeb43f6be9ffa2cb55f7a5a |
| institution | DOAJ |
| issn | 2075-4442 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
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| series | Lubricants |
| spelling | doaj-art-2ad7cb9efbeb43f6be9ffa2cb55f7a5a2025-08-20T03:08:09ZengMDPI AGLubricants2075-44422025-07-0113731410.3390/lubricants13070314Mechanisms of Adhesion Increase in Wet Sanded Wheel–Rail Contacts—A DEM-Based AnalysisBettina Suhr0William A. Skipper1Roger Lewis2Klaus Six3Virtual Vehicle Research GmbH, Inffeldgasse 21/A, 8010 Graz, AustriaSchool of Mechanical, Aerospace and Civil Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UKSchool of Mechanical, Aerospace and Civil Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UKVirtual Vehicle Research GmbH, Inffeldgasse 21/A, 8010 Graz, AustriaIn railways, problems in braking and traction can be caused by so-called low-adhesion conditions. Adhesion is increased by sanding, where sand grains are blasted towards the wheel–rail contact. Despite the successful use of sanding in practice and extensive experimental studies, the physical mechanisms of adhesion increase are poorly understood. This study combines experimental work with a DEM model to aim at a deeper understanding of adhesion increase during sanding. The experimentally observed processes during sanding involve repeated grain breakage, varying sand fragment spread, formation of clusters of crushed sand powders, plastic deformation of the steel surfaces due to the high load applied and shearing of the compressed sand fragments. The developed DEM model includes all these processes. Two types of rail sand are analysed, which differ in adhesion increase in High-Pressure Torsion tests under wet contact conditions. This study shows that higher adhesion is achieved when a larger proportion of the normal load is transferred through sand–steel contacts. This is strongly influenced by the coefficient of friction between sand and steel. Adhesion is higher for larger sand grains, higher sand fragment spread, and higher steel hardness, resulting in less indentation, all leading to larger areas covered by sand.https://www.mdpi.com/2075-4442/13/7/314wheel–rail contactlow adhesionDiscrete Element Method |
| spellingShingle | Bettina Suhr William A. Skipper Roger Lewis Klaus Six Mechanisms of Adhesion Increase in Wet Sanded Wheel–Rail Contacts—A DEM-Based Analysis Lubricants wheel–rail contact low adhesion Discrete Element Method |
| title | Mechanisms of Adhesion Increase in Wet Sanded Wheel–Rail Contacts—A DEM-Based Analysis |
| title_full | Mechanisms of Adhesion Increase in Wet Sanded Wheel–Rail Contacts—A DEM-Based Analysis |
| title_fullStr | Mechanisms of Adhesion Increase in Wet Sanded Wheel–Rail Contacts—A DEM-Based Analysis |
| title_full_unstemmed | Mechanisms of Adhesion Increase in Wet Sanded Wheel–Rail Contacts—A DEM-Based Analysis |
| title_short | Mechanisms of Adhesion Increase in Wet Sanded Wheel–Rail Contacts—A DEM-Based Analysis |
| title_sort | mechanisms of adhesion increase in wet sanded wheel rail contacts a dem based analysis |
| topic | wheel–rail contact low adhesion Discrete Element Method |
| url | https://www.mdpi.com/2075-4442/13/7/314 |
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