Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720709
Title: Damage detection and damage evolution monitoring of composite materials for naval applications using acoustic emission testing
Author: Angelopoulos, Nikolaos
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2017
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Thesis embargoed until 01 Dec 2017
Access from Institution:
Abstract:
Maritime transport has profound importance for the world economy. Vessels of all sizes constantly transport large numbers of passengers and goods across the sea, often under adverse operational conditions. Vessels need to exhibit high levels of reliability, availability, maintainability and safety (RAMS). However, at the same time their performance needs to be optimised ensuring the lowest possible fuel consumption with the maximum operational capacity and range without compromising RAMS. Sweating of naval assets and profitability should be maximised for the operator ensuring investment in future projects and supporting the growth of maritime transport and world economy as a whole. Vessels have been traditionally manufactured using naval steel grades such AH, DH and EH. Smaller leisure and specialised purpose vessels such as patrol boats, etc. have been built using fibre-reinforced composite (FRC) materials. This trend is gradually penetrating the market of larger commercial vessels including freight and cruise ships. However, these are still the early days and further investigation of the optimum FRC manufacturing techniques and mechanical properties together with an in-depth understanding of the damage mechanics are required before such materials can become more commonplace. This project has investigated different glass FRCs using different manufacturing techniques. Glass fibres are preferred due to their lower cost in comparison with carbon fibres. The use of carbon FRCs in maritime applications is limited to the fabrication of racing and high performance speedboat vessels. Samples manufactured under laboratory conditions have been compared with those manufactured by a shipyard. It has been seen that the in-house samples had generally superior performance. Steel-to-composite joints have also been assessed including different designs. The effect of different features in the design such as drilled holes and bolts on the mechanical performance of the manufactured samples has also been evaluated. The damage mechanisms involved during damage propagation and features causing damage initiation have been considered. Damage initiation and subsequent evolution have been monitored using acoustic emission (AE). Various signal processing approaches have been employed (manual and automatic) for optimum evaluation of the AE data obtained in a semiquantitative manner. It has been shown that AE could be applied effectively for structural health monitoring of naval structures in the field. Several factors and parameters that need to be considered during acquisition and analysis have been successfully determined. The key results of the study together with mechanical testing and characterisation of samples employed are presented in summarised form within the present thesis.
Supervisor: Not available Sponsor: European Commission FP7 project MOSAIC
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.720709  DOI: Not available
Keywords: TN Mining engineering. Metallurgy ; VM Naval architecture. Shipbuilding. Marine engineering
Share: