The understanding of how the friction management products grease and friction modifiers work and effectively test Wheel rail contact thesis products is necessary to improve the performance of a railway network.
This significantly affects the wheel-rail contact conditions such as damage initiation, high contact temperature due to frictional rolling, and wear of the rails.
The modified pendulum was able to detect the difference between a dry and lubricated rail gauge face. Moreover the analytical method was also applied to evaluate the temperature rise on the rail, respectively. The papers presented concern the effective benchmarking of wayside curve lubricants grease in a twin disc test rig.
Three-dimensional 3D elasto-plastic finite element model FEM was used in this thesis to examine the wheel-rail contact on a straight track.
The more complicated rolling phenomenon of the wheel on a curved track was also investigated numerically in this thesis. The mechanical and thermal properties of the rail material were governed by temperature. The results showed the difference in operational behaviour of the chosen TOR-FM when used in a laboratory versus the field.
A novel treatment method to protect the rail head using hydrophobic solutions was investigated using twin disc and pendulum testing.
Furthermore, the effects of contact curvature on the contact zone and contact pressure were also observed, and the response of material was predicted by a shakedown diagram. Some sub-components of the track such as railpads, sleepers and ballast were also included in the model.
Moreover the formation of white etching layer WEL on the rail surface combined with rolling cycles can potentially lead to rail damage. Finally a 3D coupled thermal-mechanical FE model was developed to examine the temperature rise due to high adhesion contact and Wheel rail contact thesis thermal influence on residual stress-strain, wear and rail life.
The current thesis focuses on modelling wheel-rail contact under high adhesion condition, and explanation of the subsequent damage formation on the rail.
Canted and non-canted rails were considered to determine the effect of the cant angle on the contact stress levels. The new and worn profiles were considered in the simulation to examine different contact situations: Material responses, the formation of rail corrugation and fatigue defects on both low and high rails were anticipated based on the results from simulations.
A new method for assessment of grease carry down has been trialled in the field. The model provides a better understanding of the influences of high adhesion condition on contact stress states, damage initiation and also temperature rise on the rail. However, the benefits of use in the field are questioned.
Due to the influences of super-elevation also called track cantangle of attack AOA and rail cant, stress states on the high rail are significantly different from that on the low rail.
The influence of repeated multi-passes from multiple wheels on one point of the rail was also taken into account. The numerical model employed the moving heat source code developed by Goldak. They compare the effectiveness of several greases in respect to adhesion, wear protection and retentivity number of cycles of adequate lubrication.
Tests showed that these products, when sufficiently diluted, do not reduce friction to dangerous levels or isolate the vehicle from the track circuit.The contact locations between wheel and rail represents the contact situation in a low radius curve for the first and second wheel-set of the leading bogie of an X1.
Recommended Citation. Vo, Khoa Duy, Damage analysis of wheel/rail contact associated to high adhesion condition, Doctor of Philosophy thesis, Faculty of Engineering and Information Sciences, School of Mechanical, Materials and Mechatronic, University of Wollongong, Adhesion in the wheel–rail contact.
Yi Zhu. Doctoral thesis. Department of Machine Design. Royal Institute of Technology. SE 44 Stockholm. TRITA – MMK ISSN As the wheel–rail contact is an open system, the adhesion between the wheel and rail is inevitably affected by contaminants.
The contact patch for a standard profile rail and wheel (and 11 tonnes contact force) is elliptical with 18 x 11 mm for the major and minor es of the ax ellipse . Adhesion in. the. wheel–rail contact under contaminated conditions Yi Zhu.
Licentiate thesis. Department of Machine Design. Royal Institute of Technology. Abstract.
Friction management and control of adhesion at the wheel/rail interface is vital for an efficient and cost effective railway network. The understanding of how the friction management products (grease and friction modifiers) work and effectively test these products is necessary to improve the performance of a railway network.Download