A new stochastic systems approach to structural integrity

This paper develops improved stochastic models for the description of a large variety of fatigue crack growth phenomena that occur in components of considerable importance to the functionality and reliability of complex engineering structures. In essence, the models are based on the McGill-Markov and Closure-Lognormal stochastic processes. Not only do these models have the capability of predicting the statistical dispersion of crack growth rates, they also, by incorporating the concept of crack closure, have the capability of transferring stochastic crack growth properties measured under ideal laboratory conditions to situations of industrial significance, such as those occurring under adverse loading and/or environmental conditions. The primary data required in order to be in a position to estimate the pertinent parameters of these stochastic models are obtained from a statistically significant number of replicate tests. In this paper, both the theory and the experimental technique are illustrated using a Ti-6Al-4V alloy. Finally, important structural integrity, reliability, availability and maintainability concepts are developed and illustrated

A comparative study of French and UK Government programmes to tackle the physical, management, and social problems of postwar social housing estates

This thesis examines the impact of the Estates Action (EA) programme in the UK, and Developpment Social des Quartiers (DSQ) programme in France, on run down, post war, marginalised estates. Its focus is the housing management aspects of the problems on the estates. It examines the methodological problems associated with comparative studies of housing estates, then sets out a comparative analysis of the origins, development, and nature of the estates under consideration. The origins and structure of the DSQ/EA programmes are explained, and a descriptive evaluation is given of their impact, based partly 12 detailed case studies. There is considerable use of primary documentary sources, and interviews with both local and national government officials, including with over 100 housing and other agents on the estates. It also draws on published reports and other material. I argue that there are a number of factors, shared in both counties, which create the problems: - the physical state of the estate itself - poor management of the estate - failure to carry out the necessary infrastructural works to accompany construction - the encouragement of low cost home ownership as the natural and desired tenure - the need to fill the empty properties with anyone who would pay rent, allied with social and racial "dumping". The provision of EA/DSQ resources to the estates was due to wider imperatives than simply housing problems of voids or disrepair -rather it was the problems of high pockets of unemployment, rising crime rates, and the notion of "social exclusion". Successful aspects of the programme include physical rehabilitation, new devolved management, and better infrastructural provision, although these were often quickly subject to vandalism. Less successful were the attempts to reduce residualisation by tenure mix or social engineering of allocations. Voids were tackled by a variety of imaginative solutions, and the programmes increasingly included measures to tackle the underlying problems of crime and economic marginalisation. The most effective remedies were those which involved wholesale remodelling of estates, with demolitions and the introduction of new homes, including new tenures. This type of solution is most likely to be effective in the worst estates; though the less radical measures will be effective in the less problematic areas. Note: Throughout this thesis French expressions are generally translated, and where appropriate the original is given between square brackets; for example: APL Housing Benefit [Aide Personalise a Logement] In addition, any price comparisons made at an assumed exchange rate of £1 =F10, irrespective of the year of comparison