Dedicated to my parents, who taught me what personal sacrifice is, to my grandfather who taught me what pride is and to my sister who taught me what strength is.Αφιερώνεται στους γονείς μου που μου δίδαξαν τι σημαίνει αυτοθυσία, στον παππού μου που μου δίδαξε τι σημαίνει περηφάνια και στην αδερφή μου που μου δίδαξε τι σημαίνει δύναμη i
SUMMARYAlthough maintenance tries to prevent them, failures regularly occur in practice. Prevention prerequisites insight on "how" a failure occurs. Failure mechanisms (FM) describe how components fail. However, operators or technicians as the first people to deal with a failure, normally lack the knowledge to assess FM that act on a material level. Current failure reporting is typically done by entering a failure type/failure mode/cause manually or selecting from a drop-down menu. However, this process has been reported as problematic by several industries. The current thesis attempts to propose a treatment for the above problematic area which is addressed in the first chapter. Many companies face the same failure reporting problem. Several have been approached to discuss their needs and the means to satisfy them. Chapter 2 presents the stakeholders of this project and identifies their needs in different levels. The treatment proposed here is the FAME-X Expert System (ES) which is designed to assist operators in assessing the appropriate FM. Operators can access FAME-X from their mobile devices via the Web and perform an on-site failure analysis. Chapter 3 introduces the idea behind the ES which is simply that failure analysis expertise is transferred from a human to a computer in the form of heuristics. This knowledge is then stored in the computer and users call upon the computer for specific advice as needed. The computer asks questions regarding failure diagnostic characteristics, makes inferences and arrives at a specific conclusion. Then, like a human consultant, it gives advices on the most dominant FM given the provided evidence and explains, if necessary, the logic behind the advice. Chapter 4 defines the design cycle of FAME-X which is composed by the following tasks: problem investigation, treatment design and treatment validation. The structure of the thesis corresponds to these tasks. The content of Chapters 1 until 3 is dedicated to problem investigation. The rest of the chapters are addressing the two remaining tasks. The actual design of FAME-X (i.e. treatment design) starts in Chapter 5 where the requirements for the design are set. FAME-X system is based on an extensive study of failure diagnostic characteristics and their contribution to FM. In contrast to failure modes, the proposed FM approach enhances the decision making upon proper remedial actions. Chapter 6 formulates the failure analysis knowledge which is then transformed into heuristics in order to be able to be inserted into the computer. The detailed design of the computer is presented in Chapter 8 where the various modules comprising an ES are developed an intergraded. This chapter concludes the tre...