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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Contribution à la quantification des programmes de maintenance complexes / Contribution to complex maintenance program quantification

Ruin, Thomas 09 December 2013 (has links)
Face aux nouveaux cadres législatifs ou environnementaux dans lesquels ils doivent évoluer, les systèmes industriels actuels sont, en plus d'être contraints par des exigences classiques de productivité et de cout, sujets au respect de nouvelles exigences relatives à la sûreté, la sécurité ou au développement durable notamment. Pour répondre à ces exigences et améliorer la maitrise des performances de ses systèmes, EDF souhaite faire évoluer sa démarche d'Optimisation de la Maintenance Basée sur la Fiabilité vers une nouvelle méthode. Cette méthode nécessite en autre la proposition d'une approche outillée permettant de quantifier a priori les programmes de maintenance (CMPQ) sur ses systèmes par rapport aux indicateurs de performance attendus (KPIs). Cet outillage fait l'objet de cette thèse financée dans le cadre du GIS 3SGS - projet DEPRADEM 2. Après avoir généralisé les besoins d'EDF en regard de la CMPQ, nous proposons une identification de la connaissance générique nécessaire pour évaluer les KPI. Afin d'aboutir à un outil permettant l'automatisation de ces études de CMPQ, cette connaissance générique est ensuite modélisée sur la base de deux langages : le langage semi-formel SysML capitalisant, par l'intermédiaire de différents diagrammes, la connaissance statique, interactionnelle et comportementale ; et le langage AltaRicaDF, supportant un modèle dynamique permettant d'évaluer les KPIs par simulation stochastique. La création de ce modèle dynamique à partir des différents diagrammes est basée sur un mapping entre les concepts d'intérêt des deux langages. La démarche dans sa globalité est validée à la CMPQ d'un cas d'étude fourni par EDF : le système ARE / To face with new legislatives and environmental contexts in which they have to operate, it is needed now that the industrials systems have to satisfy to many different requirements and constraints. Thus, these requirements are not only conventional ones such as availability and costs, but also emergent ones such as safety and sustainability. This report implies for the specific French company EDF (energy power supplier) to evolve from its usual approach of reliability centered maintenance (RCM) to a new approach. It is consisting mainly in developing a tool able to support the Complex Maintenance Programs Quantification (CMPQ). This Ph.D. is dealing with this the engineering and deployment of this tool in the frame of the GIS 3SGS - DEPRADEM 2 project. The first step of the work is to generalize EDF needs, then to propose a framework enabling to identify required generic knowledge needed to assess the Key Performances Indicators (KPIs) for supporting quantification. The next step is to model the generic knowledge in two complementary ways: a formalization of the static, interactional and behavioral knowledge based on different SysML diagrams; and a formalization of the dynamic and executable knowledge formalized by AltaRicaDF (ADF) language, allowing to perform stochastic simulation and to assess required KPIs. The path to elaborate dynamic executable vision from SysML diagrams is released by means of rules between each element of interest of both languages. All this approach/tool is applied to a specific EDF case study: the ARE system
2

Periodical Maintenance Modelling and Optimisation Assuming Imperfect Preventive Maintenance and Perfect Corrective Maintenance / Periodisk underhållsmodellering och optimering givet ofullständigt förebyggande underhåll och perfekt avhjälpande underhåll

Engvall Birr, Madeleine, Lansryd, Lisette January 2021 (has links)
In this paper, a periodic maintenance model is formulated assumingcontinuous monitoring, imperfect preventive maintenance (PM) and perfect correctivemaintenance (CM) using three decision variables, (I, N, Z). The model is derived in aninfinite horizon context where the mean cost per unit time is modelled. PM actionsare performed N − 1 times at time instants iT for i = 1, ..., N − 1, where T = ∆T · Iand ∆T is a fixed positive number representing the minimum time allowed betweenPM actions and I is a time interval multiple representing the decision of how oftenPM actions should be performed. The N:th maintenance activity is either a plannedreplacement (if Z = 0) or a corrective replacement from letting the component runto failure (if Z = 1). Imperfect PM is modelled using age reductions, either using aconstant r or a factor γ. Previous research on assumptions of these types has beenlimited as the assumptions yield models of high complexity which are not analyticallytractable. However, assumptions of this type are considered more realistic than othermore thoroughly researched assumptions, using e.g. minimal CM. Therefore, twocomplimentary optimisation methods are proposed and evaluated, namely, completeenumeration and a specially derived genetic algorithm which can be used for differentproblem sizes respectively. Carefully determined solution bounds enabled completeenumeration to be applicable for many input parameter values which is a great strengthof the proposed model. / I denna rapport modelleras en periodisk underhållsmodell baserat på antagandenakontinuerlig tillsyn,. ofullständigt förebyggande underhåll (FU) och perfektavhjälpande underhåll (AU) genom tre beslutsvariabler (I, N, Z). Modellen härledsinom ramen för en oändlig planeringshorisont där genomsnittskostnaden pertidsenhet modelleras. FU åtgärder utförs vid N − 1 stycken tillfällen vid tidpunkternaiT för i = 1, ..., N − 1, där T = ∆T · I och ∆T är ett givet positivt tal som representerarden minsta tillåtna tiden mellan FU åtgärder och I är en tidsintervallmultipelsom representerar beslutet kring hur ofta FU åtgärder ska utföras. Den N:teunderhållsåtgärden är antingen ett planerat utbyte (om Z = 0) eller ett avhjälpandeutbyte från att låta komponenten arbeta tills dess att den går sönder (om Z = 1).Ofullständigt FU modelleras genom åldersreduktion, antingen genom en konstantr eller en faktor γ. Det har visat sig finnas få tidigare studier som baseras påliknande antaganden då antaganden av denna typ resulterar i modeller av högkomplexitet som inte går att optimera analytiskt. Dock anses antaganden av dennatyp vara mer realistiska än andra mer välstuderade antaganden som exempelvisminimalt AU. Därför föreslås och utvärderas två kompletterande optimeringsmetodertill modellen, nämligen, total genomsökning och en specifikt anpassad genetiskalgoritm som kan användas för olika problemstorlekar. Genom att härleda effektivalösningsavgränsningar kunde optimering med hjälp av total genomsökning bli möjligtför många olika värden på modell parametrarna vilket är en stor fördel med denslutgiltiga modellen.

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