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Risk based approaches are gaining currency as industry looks for rational, efficient and flexible approaches to managing their structures and equipment. When applied to inspection and maintenance of industrial assets, risk based approaches differ from other approaches mainly in their assessment of failure in its wider context and ramifications. These advanced techniques provide more insight into the causes and avoidance of structural failure and competing risks, as well as the resources needed to manage them. Measuring risk is a challenge that is being met with state of the art technology, skills, knowledge and experience. The thesis presents risk based approaches to solving two specific types of problem in the management of offshore structures and equipments. The first type is finding the optimum timing of an asset life management action such that financial benefit is maximised, considering the cost of the action and the risk (quantified in monetary terms) of not undertaking that action. The approach presented here is applied to managing remedial action in offshore wind farms and specifically to corroded wind turbine tower structures. The second type of problem is how to optimise resources using risk based criteria for managing competing demands. The approach presented here is applied to stocking spares in the shipping sector, where the cost of holding spares is balanced against the risk of failing to meet demands for spares. Risk is the leitmotiv running through this thesis. The approaches discussed here will find application in a variety of situations where competing risks are being managed within constraints.

The aviation sector is looking to replace conventional metals for aircraft structures with composite materials due to the latter's potentially favourable combination of mechanical properties and low weight. However, relatively little is known about the environmental impacts and economic costs associated with composite materials displacing conventional metal in aircraft applications, and the relevant analysis models have not been well established. An integrated life cycle assessment (LCA) and life cycle costing (LCC) framework is proposed for assessing environmental and cost performances. The framework and relevant analysis models developed provide a systematic assessment of environmental and economic respective aspects associated with a given product or process. A graphical tool was developed to represent an eco-efficiency (EE) comparison based on the integration of the LCA and LCC results, which is a sustainability measure combining environmental and economic performances for comparing the different alternatives to support material selection. The displacement of a conventional aluminium aircraft door by a composite door on a life cycle basis is presented as an example of the use of this framework. The scenario analysis, sensitivity analysis and Monte Carlo Simulation as support analyses are carried out to address the data uncertainty. The graphical visualisation tool demonstrates the integrated environmental and economic performances of this displacement. The research found that composite aircraft doors could increase both environmental and financial impacts by 77% over conventional doors across the entire life cycle. The study recommended that the composite door would become favoured if a weight reduction of 45% could be achieved for the future composite door after optimisation and continuous improvement. The EE analysis result demonstrated that, among all the composite door scenarios with various composite waste recycling methods, the pyrolysis recycling with equal quality carbon fibre substitution scenario presented the best environmental and economic performances. This study presents the pioneering application of a comprehensive framework for analysing aircraft components, while also introducing novel cost and environmental impact models. Notably, this research focuses on addressing the end-of-life recycling challenges specific to composites. This study contributes a new database for inventory datasets and demonstrates a potential improvement method for future aircraft door production. The research looks at the whole aircraft supply chain with a holistic view of the materials and processes, providing a better understanding of the trade-offs and achieving sustainable decisions.

This research has been motivated by a demand from industry for an efficient decision support tool for shipyards to select and implement the right performance improvement strategies that fit the nature of their own business. This research project has developed a strategic approach, named shipyard production performance management (SPPM), to support shipyards to optimise their performance management strategy. The key functionalities of the algorithm include performance evaluation and budget optimisation for planning the improvement activities. SPPM is designed to evaluate the production performance using an advanced approach based on Key Performance Indicator (KPI) principles. The production performance of the shipyard is reviewed comprehensively from seven aspects, including Health and Safety, economic, environmental, technical, human resource, security and supply chain management. In total, there are 30 KPIs with their calculation details defined to measure the performance from these perspectives. Accordingly, the hotspots can be identified to prioritise the focus for the future improvement. This is not only to select the suitable emerging technology, but also to determine the capital investment required for such activities. How to optimise the budget for performance improvement then becomes the next question for which the shipyards need to find a solution. The budget optimisation function in SPPM has two functions named Performance Based Budgeting (PBB) and Budget Allocation Optimisation (BAO). PBB defines the total budget required with its allocation via adopting the framework of Cooperate Performance Management (CPM), while BAO applies when the total available fund is restricted. Depending on the decision context and data availability, the BAO can be performed by different calculation methods, including multi-criteria decision analysis (MCDA), utility theory and mathematical programming, for which procedures have been developed in this research. The development of SPPM is supported by a comprehensive knowledge-based that contains various well-established theories and models, practical experience shared by shipyards as well as numerous relevant researches in the field. More than just direct usage of this knowledge base, SPPM is the extension and combination of various existing theories or the application of these theories in new fields. Benefited from involvement of the shipyards, the developed algorithm has strong practicality, which has been developed as the extracted essence from intensive researches, taking into account of usefulness in measuring performance of each PPI, the data availability of the input parameters, and the level of acceptability and comprehensibility of the algorithm for users, etc. SPPM evaluate the production performance from multiple angles, such as technical, socioeconomics, sustainability, collaboration with third parties, and all the supportive and administrative activities at the shipyard, etc., and provide step-by-step instruction for the assessment. Besides, this tool has also provided the function that allows centralised performance data management. To sum up from the points above, the SPPM is an innovative and advanced strategic approach that can provide valuable support for the shipyard production performance management.

The shipping industry represents a large sector with a wide range and significant scale of impacts. This underlines the need for sustainable decision making, which ensures the economic viability of operations in the long term, whilst reducing environmental impacts and health and safety risks. The demand for integrated tools that enable decision makers to integrate a holistic set of sustainability measures has already been pointed out in the literature, ideally considering the whole life cycle. In this Thesis, a multi-criteria decision support framework has been developed to evaluate the implementation of different material options on a life cycle basis. This comprises an evaluation of Life Cycle Costs (LCC), Environmental Impacts (EI) and Risk Assessment (RA) alongside each other, explicitly accounting for uncertainties in the inputs. Subsequently, all these aspects are integrated through a Multi-Criteria Decision Analysis (MCDA) approach, allowing to account for different perspectives and priorities of the decision maker. The framework was used to evaluate High-Strength Low-Alloy steel (HSLA) and advanced composites to replace conventional steel in ship structures. Results show the potential of these materials, indicating significant financial and emission savings over the life cycle, despite their higher initial costs. However, currently uncertainties and consequently risks are present and the approach shows how to account for these depending on the priorities of the decision maker. It is demonstrated that the approach provides structured decision support for sustainable material choices. The novelty lies in integrating different sustainability aspects in one coherent framework, taking a life cycle perspective. By doing this it is possible to integrate different types of data and explicitly account for different stakeholder perspectives and decision maker priorities. Another key feature is the clear visualisation of results, facilitating transparent communication to support the decision making process. Whilst the contribution of the research presented is demonstrated for the shipping sector, the potential of applying the framework and the methodology in other industrial applications is highlighted.