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Title: Pitting and film thickness in rolling contact
Author: Foord, Colin Arthur
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1968
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The computer solution to a theory of pitting crack propagation which takes into account speed effects and fluid properties is developed, and shows fair agreement with previous experimental work. The most important section of this work is the development of a technique for measuring the shape and thickness of the three dimensional oil film produced in rolling point contact. The technique uses optical interference to obtain contour maps of the oil film produced when a steel ball rolls against a glass disc which is free to rotate on an air bearing. Excellent fringes are obtained using both monochromatic and white light. Much of the improvement over earlier fringes is due to the use of a partially reflecting chrome layer on the glass disc. The optical elastohydrodynamic film thickness measurements provide a way of evaluating the relative effectiveness of different lubricant types in producing elastohydrodynamic films. The effectiveness is expresses as a relative pressure viscosity coefficient. Over 40 lubricants including many pure compounds and high performance synthetic lubricants are evaluated.. Strong evidence for the non-Newtonian behaviour of polymer blended lubricants, and some evidence for the viscoelastic behaviour of.pure compounds is found. The contour map of the oil film provides an excellent starting point for the theoretical investigation of the elastohydrodynamic problem in point contact. A computer program for calculating the pressure field from the film thickness contour, using Reynolds' equation, is developed. Less success is achieved in the elasticity part of the problem. Finally, the further possibilities for developing both the experimental and theoretical techniques are discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available