Design and Development of an Unconventional Roller Test-rig for the Investigation of Rolling Contact Fatigue and Wear Phenomena in Railway Wheels and Rails

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The objective of this project is to design, manufacture and test an unconventional roller test-rig for the investigation of rolling contact fatigue and wear phenomena in railway wheels and rails within the framework of the "New Instrumentation for Research" program. The concept design of the proposed test-rig is presented. The test-rig has been designed with an intention to replace twin-disc machines, which are currently used for investigating rolling-sliding contact fatigue and wear characteristics of steels used in railway wheels and rails. Twin-disc machines are not suitable for rolling contact fatigue and wear investigations in the context of materials testing for railway wheels and rails, as they cannot replicate parameters in a wheel-rail contact. They also suffer from problems with respect to solution accuracy stemming from scaling of results. Conventional full-scale roller test-rigs that are used for testing real railway wheels also have several drawbacks with respect to RCF and wear testing. They are discussed in detail in the proposal. The proposed test-rig can overcome the limitations of its predecessors as it has the ability to test the fatigue and wear characteristics of materials for railway wheels and rails at contact conditions close to reality. Apart from materials testing, it can also be used for conducting general contact investigations at free rolling, braking and accelerating conditions at realistic contact loads, which makes it a multipurpose test-rig.The principle of the test-rig is validated by comparing the contact patch developed by the rollers of the test-rig with the real wheel-rail contact patch instead of verifying empirically using a model test-rig. This is because, the loads and contact parameters required for simulating rolling contact fatigue and wear phenomena in railway wheels and rails cannot be produced in a model test-rig. Finite Element calculations have been carried out to calculate the geometry of the contact patch and the results thereof are discussed in detail in the proposal. This application is therefore aimed at the second stage of the programme in which the test-rig is manufactured and a pilot project is carried out.The project is divided into three work packages (WP). WP I consists of the detailed engineering design of the test-rig based on the developed concept. In WP II, the test-rig is manufactured and commissioned. In WP III, a validation project is carried out on the test-rig to prove its ability to develop intended fatigue cracks and wear on the specimens. The complete project (WP I to WP III) is planned for 30 months. The test-rig will be made available to third party researchers after its validation.