With world shipping and other maritime based industries tending to operate assets requiring a large capital investment representing over half the total operating cost of the vessel, considering life extension at the end of a structure’s design life can postpone further capital investment and reduce the yearly operating costs of a particular asset for the owner. Despite this experience the concept of asset life extension for continued use once design life is exceeded is one which has been covered in very limited detail in the academic community. In more recent years the concept of asset life extension has become important to a growing number of maritime industries and as such has become an industry lead area for investigation, with the lead being taken by the Health and Safety Executive in the UK and other regulatory bodies abroad. The work presented here describes the investigations into life extension assessment of assets, with a special focus on the Severn class lifeboat fleet owned by the RNLI, who wish to assess the potential for life extension of this fleet to enable the continued use of a successful asset and offset a £120 million replacement program. The vessels themselves are a monolithic stiffened composite construction with a design life of 25 years. A methodology is devised which uses material static and fatigue data, environmental conditions and structural response data to determine the expected useful life of a composite structure. This methodology is then applied to the Severn class fleet by conducting experiments to determine the fatigue life of the materials through coupon tests, understanding the environmental conditions and the errors involved in predicting them and carrying out measurements of the structural response of a Severn class lifeboat whilst in service. Combining these variables using Monte Carlo simulations and the Miner’s rule allows an estimate of the useful life of the asset to be made.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:678167 |
| Date | January 2015 |
| Creators | Roberton, D. M. V. |
| Contributors | Shenoi, Ramanand |
| Publisher | University of Southampton |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://eprints.soton.ac.uk/386120/ |
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