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Lookup NU author(s): Dr Sadegh Nadimi
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Rail Sanding is a common practice in the railway industry to manipulate the friction at the wheel-rail interface during both braking and traction . Although sanding has been widely accepted as an effective material, in particular for contaminated conditions such as leaf films on the line, there is a lack of understanding on the influence of the sand characteristics. In this study, a tribological testing method, called High Pressure Torsion (HPT) , is modelled using Discrete Element Method (DEM). The HPT method is a means of quantifying the friction between two specimens, in presence of third body materials. In this approach, the torque required to gently twist a specimen in contact with another specimen under a given normal pressure in an annulus is measured. This allows the calculation of shear stresses in the contact and therefore characterisation of the friction. Here, the specimens are made from wheel and rail materials and the third body material is a different type of sand particles. To systematically study the mechanisms of traction enhancement of sand particles in the rail-wheel interface, a DEM model is developed which allows incorporation of different particle shape and the breakage of particles under loading (see Figure 1). The role of particle morphology, i.e. size and shape, is evaluated and compared with previous experimental studies . Further work will investigate extending the range of particles properties, such as material strength and fracture energy with the ultimate aim of enhancing the current engineering guidelines.
Author(s): Nadimi S, Skipper W, Ghadiri M, Lewis R
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: 8th International Conference on Discrete Element Methods
Year of Conference: 2019
Acceptance date: 21/07/2019