Huw Prosser Evans

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Worm gears used for power transmission commonly consist of a steel worm running against a bronze or phosphor bronze worm wheel. The wheel teeth are usually manufactured using an ‘oversize’ hob so that the initial elastic contact between the teeth is in the form of an ellipse with lubricant entrainment predominantly in the major axis direction. As a result(More)
The paper presents a transient analysis technique for line contact elastohydrodynamic lubrication problems using coupled elastic and hydrodynamic equations. Full coupling is made possible by use of a novel differential deflection formulation. The lubricant is treated as non-Newtonian with a non-linear Eyring-type relationship between shear stress and shear(More)
BACKGROUND Children are scheduled to receive 18-20 immunizations before their 18th birthday in England and Wales; this approximates to 13 million vaccines administered per annum. Each immunization represents a potential opportunity for immunization-related error and effective immunization is imperative to maintain the public health benefit from(More)
INTRODUCTION Incident reports contain descriptions of errors and harms that occurred during clinical care delivery. Few observational studies have characterised incidents from general practice, and none of these have been from the England and Wales National Reporting and Learning System. This study aims to describe incidents reported from a general practice(More)
Previous research provides qualitative evidence that an improved surface finish can increase the surface fatigue lives of gears. To quantify the influence of surface roughness on life, a set of AISI 9310 steel gears was provided with a near-mirror finish by superfinishing. The effects of the superfinishing on the quality of the gear tooth surfaces were(More)
The paper presents results obtained using a transient analysis technique for point contact elastohydrodynamic lubrication (EHL) problems based on a formulation that effectively couples the elastic and hydrodynamic equations. Results are presented for transverse ground surfaces in an elliptical contact that show severe ®lm thinning at the transverse limits(More)
The paper presents results obtained using a transient analysis technique for point contact elastohydrodynamic lubrication (EHL) problems based on a formulation that couples the elastic and hydrodynamic equations. Results are presented for transverse ground surfaces in elliptical point contact that show severe film thinning and asperity contact at the(More)
The paper presents numerical results for the elastohydrodynamic lubrication of gear teeth using real surface roughness data taken from micropitting tests carried out on an FZG gear testing machine. Profiles and load conditions corresponding to four load stages in the micropitting test protocol are considered. Elastohydrodynamic film thickness and pressure(More)
The paper compares the results of applying different fatigue failure models to surfaces that experience elastohydrodynamic lubrication (EHL) and have surface roughness features which are large compared with the equivalent smooth surface film thickness. The surface profiles used for the comparisons reported are taken from test gear surfaces used in an FZG(More)