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A superconducting machine is an ideal device for power generation, ship propulsion, and electric vehicles, for it would be many times smaller, lighter, and more efficient than an equivalent copper wound motor. The aim of this dissertation is to propose a design of a wholly superconducting motor with HTS tapes in the stator and HTS pucks on the rotor. Both the HTS stator windings and the magnetisation process of the HTS rotor have been modelled by implementing the critical state models using finite element method. Those models are based on a set of Maxwell’s equations incorporated with the <i>E-J</i> constitutive law. In addition, the AC losses of the stator windings were estimated. Due to the irregular field distribution from the magnetised rotor, the AC losses are too high for machine operation. Iron is used surrounding the windings to regulate the rotor field, so that the AC losses are largely reduced. A model based on an electromagnetic module was used to identify the machine parameters, such as self and mutual inductances. Experiments were carried out to measure the critical current of the stator winding. Additionally, the equivalent stator resistance was estimated based on the AC losses in the stator windings.

The wheel-rail interface is a complex component of the dynamic railway vehicle-track system. The wheel-rail interface governs the motion of a railway vehicle and is responsible for wheel and track damage such as wear and rolling contact fatigue. Wheelrail contact models are used extensively in railway engineering to calculate contact forces and stresses, in order to evaluate dynamic vehicle behaviour or assess track damage. Due to the complexity of the wheel-rail interaction, and computational limitations, all wheel-rail contact models make simplifying assumptions so that solutions may be obtained in an acceptable time. This thesis presents a survey of current wheel-rail contact models and theories, and associated literature, focussing on the various simplifications made by the different approaches. In order to allow an informative comparison of contact model performance a wheel-rail contact benchmark has been established, detailing carefully defined, challenging contact conditions. Interested parties were invited to submit solutions for the contact benchmark cases, and results from ten contributors were received and compared. From the analysis of current contact models and the contact benchmark results, a new wheel-rail contact model has been developed. The model is based on a novel relationship between the normal contact force and the intersecting volume found from virtually penetrating two, three dimensional contacting bodies. Results from the new contact model, named the 'Rectified Interpenetration method', were compared favourably to the recognised methods of Hertz and Kalker. To aid future validation of wheel-rail contact model and understanding of the wheel. rail interaction, a feasibility study of a new wheel-rail contact measurement technique has been undertaken. The technique is based on an established ultrasound method capable of measuring the normal contact pressure distribution for machined wheel and rail samples in laboratory conditions. The new technique aims to advance the state of the art to allow wheel-rail contact measurements under rolling conditions. The study concluded that there is scope for further development of the technique, and discusses the transitional difficulties in advancing the static method to rolling contacts.

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The Christchurch bridge is a lightweight and readily transportable utility which can be rapidly erected to cover a range of emergency bridging requirements. The bridge is manufactured from a weldable high tensile aluminium alloy. During large scale laboratory fatigue testing, cracks were detected in a tension cord of an I-section bridge girder where damage is most critical. The bridge girder sustained much longer critical crack lengths before failure than estimated assuming linear elastic fracture mechanics conditions and using fracture toughness data obtained from highly constrained geometries. To solve this discrepancy, the current study provides a comprehensive elastic-plastic fracture mechanics assessment of the bridge girder containing through-thickness cracks in the tension chord. Three-dimensional finite element modes of the I-section girders are analysed and a wide range of fracture parameters are evaluated. The bridge girder containing cracks is shown to be a low constraint geometry, where constraint is parameterised by the T-stress and the Q-value. The <I>J</I>-T theory enables the characterisation of the opening stress fields at a distance of 2<I>J</I>/σ<SUB>ys</SUB> ahead of the crack fronts to within 10% of the actual fields evaluated from the finite element analyses. Numerical analyses of a wide range of experimentally tested high and low constraint specimens are used to quantify the relationship between constraint and fracture toughness of the bridge material. Low constraint geometries show up to eight-fold increase in toughness in comparison with high constraint geometries. The <I>J</I>-integral values of the cracked I-section bridge girder models, calculated at the maximum strain levels obtained in the experiments, are matched with those of the specimens through the fracture toughness loci. The I-section results are within the upper boundaries of the loci. The <I>J</I>-T and <I>J</I>-Q theories provide the means of explaining, in terms of loss of constraint, why the bridge girder is able to sustain much longer cracks than first predicted. The loss of constraint enhances the fracture resistance of the bridge girder.

The thesis presents research into aspects of reliability based on monitoring the operation and management of large fleets of vehicles and equipment by a United Kingdom Government Department. A description of the Department and the results of two studies into the organisation are presented: on the data capture system used by the organisation, and on a sample of data from the organisation's data centre. The results of an equipment census are reported showing the effects of calculating mean time to failure on fails only and fails and survivor data are contrasted. Examination of the methods of analysis within the organisation have led to the need for comparison of the Weibull and negative exponential distributions in terms of their efficiency in producing parameter estimates from failure information only and fails and survivor data. Simulation experiments are described which illustrate this comparison in the presence of multiple censoring. The comparisons indicated that for complete samples the Weibull was more efficient, generally providing higher quality estimates in a shorter time, although there were circumstances when there was less to choose between the models. The studies indicated that manual transcription of data into the data capture system, sometimes repeated at differing locations led to a number of data errors; misplacement of decimal point, arbitrary zeroing of indicators (zeroing), duplicate data entry, enhancement of indicator reading (run-on), empirical conversion and estimation of data (mis-read). A series of simulations are described which investigate the effects of a corruption factor ρ for 0.00 ≤ ρ ≤ 0.10, in the absence of censoring for; the mis-placed decimal point, mis-read, run-on and zeroing corruption scenarios. Introduction of type I censoring allowed further simulation experiments, designed to determine the effects of mis-classification of fails and censored timings for a corruption factor ρ for 0.00 ≤ ρ ≤ 0.10. Profile inaccuracy was used to calculate values of for 0.00 ≤ ρ ≤ 0.10, for three corruption scenarios, which gave good agreement with values of β and θ obtained by simulation. A theory is presented which establishes the variance covariance structure of maximum likelihood estimators with those generated by simulation. A worked example is provided to compare with and to correct E[I<SUB>θθ</SUB>] in table 3 and to enhance table 1 of Watkins and Griffin (1994).