A wheel-rail interface design for enhanced S&C performance

Arthur, Kwame (2024). A wheel-rail interface design for enhanced S&C performance. University of Birmingham. Ph.D.

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Abstract

In railway engineering, the wheel-rail interaction is one of the most important research topics because it affects the safety, performance and economic efficiency of the railway. It is in-fluenced by the vibrations of the track, the suspensions of the rolling stock and the track structure. The wheel-rail impact forces can lead to significant economic loss to railway track owners as a consequence of damage to rails and sleepers. Records at Network Rail show that about 25% of annual renewal and maintenance budgets are spent on switches and crossings (S&C). To achieve a safe, reliable and efficient railway network, it is important to manage the risk caused by the wheel-rail contact complexities of the switch and crossing arrangement.
Therefore, his PhD research project was initiated to enhance S&C design by modelling a novel switch called NR60C MK2, which has an improved wheel-rail contact behaviour to address the various damage modes of the existing RT60/NR60 MK1 switch. This is the first time that modelling work has been carried out on a switch before attempts are made to bring into use on the Network Rail infrastructure. For instance, no modelling work was conducted for RT60/NR60 MK1 switches before they were brought into use. The author explores whether and how the deployment of finite element modelling using simulation tools such as Abaqus and Vampire software will allow the creation of better S&C designs for railway track in a timely manner.
For the present research, the NR60C MK2 switch was created virtually through three-dimen-sional (3D) finite element (FE) modelling. The wheel-rail contact was assessed using ABAQUS / CAE as the finite element software package that could be validated by an existing simulation. The newly developed switch (NR60C MK2) was then tested in the model space. The results predicted a significant reduction in the stress level from 1050 MPa to 580 MPa at the switch blade. Vertical displacement was similarly reduced from 0.35 mm to 0.12 mm and an improved PEEQ value of 2.1% was obtained. To enhance the switch performance, 3 mm of material (steel) was added to the switch blade. This is the first time a novel switch has been developed in the United Kingdom through the addition of a 3 mm material to the switch blade to enhance the service life of the switch. The simulation results gave a design log life of 4.95, which implied that the revised switch is predicted to have a service life that is longer than that of the existing switch.
Previous research work in this area has been focused either on modelling material strength or on carrying out vehicle dynamics simulations. The candidate is not aware of any research combining these approaches. The author of this thesis has therefore capitalised on this knowledge gap to conduct a research that will combine FEA with MB Dynamic simulation to enhance S&C performance which is the first time that material strength analysis has been
A Wheel-Rail Interface Design for Enhanced S&C Performance
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carried out vis-a-vis vehicle dynamic simulation. Therefore, to assess the efficacy of the newly developed switch, vehicle dynamic simulations using VAMPIRE® were carried out to evaluate the wear, RCF performance and derailment analysis of the new NR60C MK2 switch. The wheel-rail interface was assessed for two passenger vehicle types (Desiro and MK3) and a laden freight vehicle. The results from facing direction travel revealed no contact at the switch tip, thus eliminating any fear of switch tip damage. For all the vehicles, the NR60C MK2 switch is predicted to suffer less wear and for a shorter length along the switch planing section than the existing NR60C MK1 switch. In both the facing and trailing moves, the freight vehicle produced the worst performance, due to its high axle load and greater Primary Yaw Stiffness (PYS). However, there was a significant improvement with the application of rail lubrication. The T-Gamma value for the freight vehicle was reduced from 3018 J/m to 900 J/m. Similarly, the gauge corner wear indices at the switch planing section for all the vehicles were shown to be reduced by 30% with the application of rail gauge lubrication. The results also showed that all three vehicles used for the modelling fell below the derailment risk threshold of 1.2.
To conclude, the outcome of the simulation has enabled the author to provide recommendations to Network Rail with respect to how to enhance the performance of future S&C assets through modelling and simulation. The author has combined FEA with Multi-Body dynamic simulation to enhance S&C performance. This is the first time that material strength analysis has been carried out with respect to vehicle dynamic simulation

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):