Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Physical Asset Management (PAM) is becoming a greater concern for companies in industry today. The widely accepted British Standards Institutes’ specification for optimized management of physical assets and infrastructure is PAS55. According to PAS55, PAM is the “systematic and co-ordinated activities and practices through which an organization optimally manages its physical assets, and their associated performance, risks and expenditures over their life cycle for the purpose of achieving its organizational strategic plan”. One key performance area of PAM is Asset Care Plans (ACP). These plans are maintenance strategies which improve or ensure acceptable asset reliability and performance during its useful life. Maintenance strategies such as Condition Based Maintenance (CBM) acts upon Condition Monitoring (CM) data, disregarding the previous failure histories of an asset. Other maintenance strategies, such as Usage Based Maintenance (UBM), is based on previous failure histories, and does not consider CM data. Regression models make use of both CM data and previous failure histories to develop a model which represents the underlying failure behaviour of the asset under study. These models can be of high value in ACP development due to the fact that Residual Useful Life (RUL) can be estimated and/or the long term life cycle cost can be optimized. The objective of this thesis was to model historical failure data and CM data well enough so that RUL or optimized preventive maintenance instant estimations can be made. These estimates were used in decision models to develop maintenance schedules, i.e. ACPs. Several regression models were evaluated to determine the most suitable model to achieve the objectives of this thesis. The model found to be most suitable for this research project was the Proportional Hazards Model (PHM). A comprehensive investigation on the PHM was undertaken focussing on the mathematics and the practical implementation thereof. Data obtained from the South African mining industry was modelled with the Weibull PHM. It was found that the developed model produced estimates which were accurate representations of reality. These findings provide an exciting basis for the development of futureWeibull PHMs that could result in huge maintenance cost savings and reduced failure occurrences. / AFRIKAANSE OPSOMMING: Fisiese Bate Bestuur (FBB) is besig om ’n groter bekommernis vir maatskappye in die bedryf te word. Die Britse Standaarde Instituut se spesifikasie vir optimale bestuur van fisiese bates en infrastruktuur is PAS55. Volgens PAS55 is FBB die “sistematiese en gekoördineerde aktiwiteite en praktyke wat deur ’n organisasie optimaal sy fisiese bates, hul verwante prestasie, risiko’s en uitgawes vir die doel van die bereiking van sy organisatoriese strategiese plan beheer oor hul volle lewensiklus te bestuur”. Een Sleutel Fokus Area (SFA) van FBB is Bate Versorgings Plan (BVP) ontwikkeling. Hierdie is onderhouds strategieë wat bate betroubaarheid verbeter of verseker tydens die volle bruikbare lewe van die bate. Een onderhoud strategie is Toestands Gebasseeerde Onderhoud (TGO) wat besluite baseer op Toestand Monitering (TM) informasie maar neem nie die vorige falingsgeskiedenis van die bate in ag nie. Ander onderhoud strategieë soos Gebruik Gebasseerde Onderhoud (GGO) is gebaseer op historiese falingsdata maar neem nie TM inligting in ag nie. Regressiemodelle neem beide TM data en historiese falings geskiedenis data in ag ten einde die onderliggende falings gedrag van die gegewe bate te verteenwoordig. Hierdie modelle kan baie nuttig wees vir BVP ontwikkeling te danke aan die feit dat Bruikbare Oorblywende Lewe (BOL) geskat kan word en/of die langtermyn lewenssilus koste geoptimeer kan word. Die doelwit van hierdie tesis was om historiese falingsdata en TT data goed genoeg te modelleer sodat BOL of optimale langtermyn lewensiklus kostes bepaal kan word om opgeneem te word in BVP ontwikkeling. Hierdie bepalings word dan gebruik in besluitnemings modelle wat gebruik kan word om onderhoud skedules op te stel, d.w.s. om ’n BVP te ontwikkel. Verskeie regressiemodelle was geëvalueer om die regte model te vind waarmee die doel van hierdie tesis te bereik kan word. Die mees geskikte model vir die navorsingsprojek was die Proporsionele Gevaarkoers Model (PGM). ’n Omvattende ondersoek oor die PGM is onderneem wat fokus op die wiskunde en die praktiese implementering daarvan. Data is van die Suid-Afrikaanse mynbedryf verkry en is gemodelleer met behulp van die Weibull PGM. Dit was bevind dat die ontwikkelde model resultate geproduseer het wat ’n akkurate verteenwoordinging van realiteit is. Hierdie bevindinge bied ’n opwindende basis vir die ontwikkeling van toekomstige Weibull Proporsionele Gevaarkoers Modelle wat kan lei tot groot onderhoudskoste besparings en minder onverwagte falings.

Hasta la fecha, la industria manufacturera está mostrando un desarrollo creciente, siendo uno de los rubros que muestra cada vez más innovación en sus procesos y por ende, en los resultados de los mismos, sus productos. Sin embargo, también se reconoce la existencia de problemas y circunstancias críticas que determinan y retan la capacidad de reacción de las empresas frente a todo ello. Se considera que el área de Mantenimiento es de vital importancia para el desarrollo óptimo de los procesos de producción, pues están involucradas las diversas máquinas y equipos operados por los trabajadores. Asimismo, se busca una mejora en los procesos aplicados por parte de los operarios, estableciendo una serie de programas y actividades que mejoren el desarrollo del plan de mantenimiento en la empresa. A raíz de lo mencionado, mediante los procesos respectivos, se identificaron ciertos problemas sobre los que se desarrollarán medidas para contrarrestarlos en base a técnicas y metodologías de Ingeniería, con la finalidad de mejorar el plan de mantenimiento en la empresa en estudio. Por otro lado, para un correcto análisis, se han evaluado los indicadores clave en el área de Mantenimiento para medir y comparar el nivel en el cual estos se encuentran respecto al nivel óptimo deseado y requerido. Estos indicadores como el OEE (Overall Equipment Effectiveness), MTTR (Mean Time To Repair) y MTBF (Mean Time Between Failures) son importantes para el desarrollo de la investigación, porque medirán el resultado de la implementación de la propuesta. / Currently the manufacturing industry is showing a growing development, being one of the business sector that shows more innovation in its processes and therefore, in the results of the same, its products. However, it also recognizes the existence of problems and critical circumstances that determine and challenge the ability of companies to react to all this. The Maintenance area is considered to be of vital importance for the optimal development of the production processes, since the various machines and equipment operated by the workers are involved. Likewise, an improvement is sought in the processes applied by the operators, establishing a series of programs and activities that improve the development of the maintenance plan in the company. From the aforementioned, through the respective processes, certain problems were identified on which measures will be developed to counteract them based on engineering techniques and methodologies, in order to improve the maintenance plan in the company under study. On the other hand, for a correct analysis, the key indicators in the Maintenance area have been evaluated to measure and compare the level at which they are in relation to the desired and required optimum level. These indicators such as the OEE (Overall Equipment Effectiveness), MTTR (Mean Time To Repair) and MTBF (Mean Time Between Failures) are important for the development of the research, because they will measure the result of the proposal implementation. / Trabajo de Suficiencia Profesional

Syfte: En fasad måste vara robust för att fylla sin funktion och materialet måste kunna stå emot angrepp utifrån, biologiska, kemiska och fysikaliska faktorer. Trä och tegel är eftertraktade som fasadmaterial för dagens nybyggda bostadshus. Eftersom olika material reagerar olika på angrepp är det viktigt att det finns skillnader i underhållsstrategier beroende på vilket fasadmaterial som används. Underhållsarbetet är en faktor som påverkar beslutet på fasadmaterial. Undersökningen ger ett underlag inför valet mellan materialen genom att utveckla underhållsstrategier för respektive material. Metod: För att uppnå målet med arbetet har tre metoder använts för att samla in empiri Dessa är litteraturstudie, intervjuer och dokumentanalys. I litteraturstudien samlades information från olika källor på internet in. Dessa källor hjälpte till att bygga ett teoretiskt ramverk om fastighetsförvaltning och underhållsstrategier. Dokumenten och intervjuerna gav praktisk kunskap om förhållningssätt till underhåll. Metoderna var lämpliga eftersom de tillsammans gav teoretisk såväl som praktisk kunskap kring material och underhåll. Den insamlade empirin analyserades och jämfördes för att kunna besvara frågeställningarna och uppnå målet. Resultat: Idag finns olika underhållsstrategier på trä- och tegelfasader. Den generella åsikten är att trä kräver fler underhållsåtgärder än tegel. Det har dock visat sig att det även förekommer problem med till exempel frostsprängning i större omfattning än vad som tidigare antagits. Underhållsplaner upprättas ofta efter grundlig undersökning av en byggnads egenskaper och kartläggning av dess underhållsbehov. Dessa planer används inte regelbundet hos förvaltningsföretag men det finns en önskan bland vissa förvaltare att ha en mer strukturell underhållsplanering i framtiden. Kategorisering av skador och tillkommande underhållsåtgärder kan användas vid upprättande av underhållsplaner. Ett sådant system är Monument Damage Diagnosis System, förkortat MDDS. Underhållsplaner kan också utformas som stegvisa processer som kan användas tillsammans med databaser över fasadens egenskaper och nödvändiga underhållsåtgärder. Konsekvenser: Denna rapport kommer att ge aktörer inom byggbranschen kunskap och olika strategier vid fasadunderhåll. Konsekvenserna blir att: Företag inom byggbranschen upprättar underhållsplaner mer i framtiden. Det upprättas strukturerade bedömningar om risker kopplade till material, byggnadsdel och yttre påverkan. För- och nackdelarna med trä- och tegelfasader uppmärksammas i högre grad än idag. Många riskfaktorer för tegel såsom frostsprängning har tidigare inte beaktats tillräckligt. Det rekommenderas att byggföretag tar till sig den forskning som finns av underhåll av trä- respektive tegelfasader. Eftersom trä är billigare än tegel i byggskedet men dyrare vid underhåll behöver dessa företag göra fler undersökningar om båda materials för- och nackdelar ur ekonomisk synpunkt. Byggföretag behöver om förutsättningarna finns även upprätta underhållsplaner eftersom dessa planer leder till att fel upptäcks tidigare och därmed minskar kostnaderna på lång sikt. Begränsningar: Resultatet är enbart tillämpbart på fasader av trä och fasader av tegel.  Vidare kan resultatet bara tillämpas på bostadshus eftersom inga andra byggnadstyper har undersökts. Underhållsstrategin som utvecklats i rapporten kan i grunden användas i alla typer av klimat dock måste alltid lokala klimatförhållanden beaktas när strategin appliceras i praktiken. Att upprätta en underhållsplan kräver även en god ekonomi därför är det inte säkert att rapportens underhållsstrategi alltid kan upprättas i verkligheten om det finns ekonomiska hinder.  Litteraturstudien har studerat underhållsstrategier på global nivå medan dokumentanalysen och intervjuerna har fokuserat på de lokala förhållandena i Sverige. / Purpose: A façade must be robust to be able to fulfil its role and the material must be able to withstand exterior threats. These threats could be biological, chemical, or physical. Wood and brick are popular as façade materials when it comes to the newly constructed residential buildings of today. Since different materials react different on threats it is vital that there are separate maintenance strategies depending on the choice of façade material. The examination gives the choice between the materials a basis by developing maintenance strategies for respective material Method: To achieve the goal of the project, three methods have been used to collect empirical data. These methods are literature study, interviews, and document analysis. In the literature study, information from different sources on the internet were collected. The sources helped building a theoretical about property management and maintenance management. The document and interviews provided practical knowledge about maintenance approaches. The methods were suitable since together they provided both theoretical and practical knowledge about materials and maintenance. The collected data was analysed and compared to answer the questions and achieve the projects goal. Findings: Today there are different maintenance strategies for wood and brick facades. The general opinion is that wooden facades require more maintenance than brick facades. Although brick facades have had more problems with for example frost shattering than what was assumed before. Maintenance plans are often established after thorough investigation of a building’s properties and mapping of its maintenance needs. These plans aren’t used regularly among property managers but there’s a wish among some of them to have more structural maintenance planning in the future. Categorization of damages and additional maintenance activities can be used when establishing maintenance plans. One such system is Monument Damage Diagnosis System, abbreviated MDDS. Maintenance plans could also be formulated as step-by-step processes that could be used together with databases of a façade's properties and necessary maintenance actions. Implications: This study will give actors in the construction industry better knowledge about different strategies for façade maintenance. The consequences will be: That companies in the construction industry establish maintenance plans more in the future. That structural evaluations of risks depending on material, building component and external influence are established That strengths and weaknesses with wooden facades and brick facades are paid attention to more in the future. Many risk factors affecting brick facades has not been sufficiently acknowledged before. It is recommended that construction companies take note of current research on maintenance of wooden and brick facades. Since wood is cheaper to build with but more expensive to maintain than brick companies need to do more studies about these materials strengths and weaknesses. Construction companies also need to establish and follow maintenance plans if the conditions are right since that would lead to damages being discovered earlier and therefore decreases costs in a long term. Limitations: The result is only applicable on wooden and brick facades. Furthermore, the result can only be applied on residential houses since no other type of building has been examined. The maintenance strategy that has been developed in the report is in can be used in all climates, but local climate circumstances must always be considered then the strategy is applied in practice. Establishing a maintenance plan requires a good economy therefore it is not certain that the report’s maintenance strategy will always be possible to establish in reality if there are economical limits. The literature study has examined maintenance strategies on a global scale while the document analysis and the interviews has focused on the local circumstances in Sweden.

No description available.

Actuellement, la compétition entre les entreprises se traduit par la révision des stratégies industrielles courantes dans le but d’améliorer simultanément les plans de production et de maintenance. En réalité, la non-satisfaction du client dans les délais est due souvent à des critères aléatoires liés essentiellement à la demande et aux défaillances soudaines des systèmes de production. Par conséquent, il est nécessaire de développer des politiques de maintenance intégrées à la production en tenant compte des contraintes liées au stockage, à la demande et au taux de défaillance. Dans ce travail, nous nous intéressons à une problématique industrielle qui s’articule autour du développement de différentes politiques de maintenance intégrées à la production. Le système considéré consiste en une machine fabriquant plusieurs types de produits, dans l’optique de satisfaire des demandes aléatoire avec des niveaux de service donnés. On note que l’originalité de notre étude, par rapport à l’existant en littérature dans le domaine de la maintenance intégrée à la production, consiste à considérer un système à multi-produits. Dans cette étude nous avons développé et optimisé analytiquement des politiques de production pour un système à multi-produits devant satisfaire plusieurs demandes aléatoires caractérisant respectivement différentes clients. Ces politiques consistent à établir des plans périodiques de production pour chaque produit, minimisant les coûts liés à la production et le stockage tout en satisfaisant un taux de service prédéfini pour chaque produit. Par la suite, en tenant compte de l’influence des plans économiques de production obtenus sur l’évolution de la dégradation du système de production, nous avons développé des stratégies optimales de maintenance. Plusieurs scénarios ont été étudiés selon les durées des sous-périodes de production et le coût de setup de chaque produit. En fin, des études de cas ont été traitées afin de confronter les résultats analytiques établis / Currently, the competition between companies is reflected in the revision of the current industry strategies to improve the planning of production and maintenance. In fact, the non- satisfaction of the customer on time is often due to a random demand or a sudden failure of production system. Therefore, it is necessary to develop new maintenance and production strategies. In this memory, we treat some maintenance policies integrated with production for a manufacturing system. This paper deals with the problem of maintenance strategy and production planning for a multiple-product manufacturing system. The manufacturing system under consideration consists of one machine which produces several products in order to satisfy random demands corresponding to every product. The significance of the present study is that the study deals with the case of a system which produces several products. In this study we have developed and optimized analytically production policies for a multiple-product manufacturing system, in order to meet several random requests characterizing respectively different customers. These policies consist of establishing periodic production plans for each product, minimizing the costs of production and storage while meeting predefined service level for each product. Subsequently, we have developed optimal strategies of maintenance, taking into account the influence of economic production plans obtained, on the evolution of the degradation of the production system. Several scenarios have been studied according to the durations of the sub-periods of production and the cost of set-up of each product. In the end, case studies were treated in order to compare the developed analytical results

The research topic is: Tools for the revision of a maintenance strategy for an explosives manufacturing plant, using asset management principles. This research has specific reference to the SASOL Prillan plant based in SASOL, Sasolburg. The purpose of this research is to identify tools for the revision of a maintenance strategy for an explosives manufacturing plant, using asset management principles. These tools must be aimed to increase the proactive work capacity index, Figure 3, and to identify and/or develop tools that can be used by the engineering team of this explosives manufacturing plant to increase equipment reliability and performance. In this research assets include people. The meaning and application of asset management principles were researched and the tools needed to combine existing efforts and future needs are discussed. The human element to ensure the successful implementation of an asset management culture was researched and attributes of leaders and a change model is presented. This research was done into the wider engineering management discipline and not only maintenance. The method used to gather data was by means of interviews of a sample group within this organization. As this manufacturing unit makes use of subject matter experts, these support functions and plant personnel that were not interviewed, were issued with questionnaires to ensure that the sample group is a fair representation of the total manufacturing facility. To obtain a holistic view of potential shortcomings within the current maintenance strategy, all disciplines and levels within this operation were interviewed and commonalities of various asset management models were determined and used to define existing problem areas. This data was used to determine statistical correlations. The case study presented in Chapter 1 indicates that there is a case for change that can improve the proactive work capacity index of the engineering team. The results of this research confirm that there is in fact a real requirement to increase spares accuracy, improve on technical training as well as a need to establish visual performance indicators (dashboard) to measure overall equipment efficiency with the goal toTools for the revision of a maintenance strategy for an explosives manufacturing plant, using asset management principles increase equipment reliability and performance. The technical training referred to in this research reflects on training of people on equipment after investment in new technology. The current spares holding strategy is lacking equipment description accuracy. Furthermore, it is recommended that the implementation of career paths and development plans for individuals must be developed to create an environment of learning. The use of user status information captured on the computerized maintenance management system (SAP R/3) can add to the management of works orders and indicate where the focus must be to complete overdue work orders. Open work orders should be used to manage expenditure, to measure planning efficiency and to manage the cash flow of the business. The use of overall equipment efficiency and engineering efficiency measures is recommended and must be visually displayed on a “dashboard”. It was recommended that the engineering and operations personnel of this manufacturing plant be trained in asset management principles and that balanced scorecards are developed to ensure that the strategies of the various departments are aligned with the business strategy. Diagram 1 best illustrates the thinking and process flow of this research. The flow diagram shows five distinct stages and the appropriate objectives and/ or elements that were considered. The dissertation is also structured in this manner. All abbreviations, acronyms and definitions used in this document were listed in APPENDIX B / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.

The research topic is: Tools for the revision of a maintenance strategy for an explosives manufacturing plant, using asset management principles. This research has specific reference to the SASOL Prillan plant based in SASOL, Sasolburg. The purpose of this research is to identify tools for the revision of a maintenance strategy for an explosives manufacturing plant, using asset management principles. These tools must be aimed to increase the proactive work capacity index, Figure 3, and to identify and/or develop tools that can be used by the engineering team of this explosives manufacturing plant to increase equipment reliability and performance. In this research assets include people. The meaning and application of asset management principles were researched and the tools needed to combine existing efforts and future needs are discussed. The human element to ensure the successful implementation of an asset management culture was researched and attributes of leaders and a change model is presented. This research was done into the wider engineering management discipline and not only maintenance. The method used to gather data was by means of interviews of a sample group within this organization. As this manufacturing unit makes use of subject matter experts, these support functions and plant personnel that were not interviewed, were issued with questionnaires to ensure that the sample group is a fair representation of the total manufacturing facility. To obtain a holistic view of potential shortcomings within the current maintenance strategy, all disciplines and levels within this operation were interviewed and commonalities of various asset management models were determined and used to define existing problem areas. This data was used to determine statistical correlations. The case study presented in Chapter 1 indicates that there is a case for change that can improve the proactive work capacity index of the engineering team. The results of this research confirm that there is in fact a real requirement to increase spares accuracy, improve on technical training as well as a need to establish visual performance indicators (dashboard) to measure overall equipment efficiency with the goal toTools for the revision of a maintenance strategy for an explosives manufacturing plant, using asset management principles increase equipment reliability and performance. The technical training referred to in this research reflects on training of people on equipment after investment in new technology. The current spares holding strategy is lacking equipment description accuracy. Furthermore, it is recommended that the implementation of career paths and development plans for individuals must be developed to create an environment of learning. The use of user status information captured on the computerized maintenance management system (SAP R/3) can add to the management of works orders and indicate where the focus must be to complete overdue work orders. Open work orders should be used to manage expenditure, to measure planning efficiency and to manage the cash flow of the business. The use of overall equipment efficiency and engineering efficiency measures is recommended and must be visually displayed on a “dashboard”. It was recommended that the engineering and operations personnel of this manufacturing plant be trained in asset management principles and that balanced scorecards are developed to ensure that the strategies of the various departments are aligned with the business strategy. Diagram 1 best illustrates the thinking and process flow of this research. The flow diagram shows five distinct stages and the appropriate objectives and/ or elements that were considered. The dissertation is also structured in this manner. All abbreviations, acronyms and definitions used in this document were listed in APPENDIX B / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.

This study aims to identify business opportunities created by digitalization. The purpose is to evaluate how these opportunities could be utilized, by identifying areas of improvements in the service portfolio. This study is a qualitative case study with an abductive approach, mainly using semi-structured interviews to collect data. The case study was conducted at ABB Industrial Automation Services, where the new Collaborative Operations Center was studied. The data was analyzed from a systems thinking perspective, using a Rich Business Framing sessions as an evaluation platform. The results illustrate how difficult the transition towards a more digitalized industry is. This stems from how different customers have reached different levels of automation in their plants. Therefore, the service portfolio must be flexible and agile, in order to cater to the different customer segments. This case study identified three customer segments, one focusing on internal activities, while the other two consist of customers that have reached different levels of maturity within digitalization. Different value potentials were identified, leading to a proposal of a service portfolio. The systems thinking approach was then evaluated, leading to the conclusion that it is a useful tool, but a time-consuming process. / Denna studie går ut på att identifiera affärsmöjligheter skapade av digitalisering. Syftet är att utvärdera hur dessa möjligheter kan utnyttjas, genom att identifiera förbättringsområden i serviceportföljen. Denna studie är en kvalitativ fallstudie med en abduktiv karaktär, där huvudsakligen semistrukturerade intervjuer användes för att samla data. Fallstudien genomfördes på ABB Industrial Automation Services, där det nya Collaborative Operations Center studerades. Den samlade informationen analyserades från ett systemtänk perspektiv, där en Rich Business Framing session användes som utvärderingsverktyg. Resultatet illustrerar hur svår övergången mot en mer digitaliserad industri är. Denna svårighet har sin grund i hur olika kunder har nått olika nivåer av automationsgrad i deras anläggningar. Detta leder till att serviceportföljen måste uppfylla vissa krav, som att vara flexibel och anpassningsbar, för att nå de olika kundsegmenten. Denna fallstudie identifierade tre kundsegment, där en fokuserar på interna aktiviteter och de andra två består av kunder som kommit olika långt inom digitalisering. Olika värdepotentialer har identifierats, vilket ledde till ett förslag av en serviceportfölj. Systemtänk synsättet har sedan utvärderats, vilket resulterade i slutsatsen att det är ett användbart verktyg, även om processen är tidskrävande.

Le milieu hospitalier est un monde à la fois sensible et complexe, sensible parce que la vie humaine est en jeu et complexe parce que les équipements médicaux augmentent en nombre et en complexité technique. Ainsi, afin de préserver le bon état de fonctionnement de ces équipements et à un niveau élevé de disponibilité, leur entretien est devenu l'une des préoccupations majeures des responsables de l’hôpital. L’objectif de cette thèse est de proposer, aux responsables de maintenance biomédicale dans les établissements de soins, des outils d’aide à la décision qui permettent une meilleure maitrise des coûts. Ceci en assurant la sécurité des patients et des utilisateurs et en maintenant des performances optimales de l’ensemble des équipements médicaux. Tout d’abord, une heuristique a été proposée pour le choix de l’internalisation ou de l’externalisation de la maintenance et pour la sélection du contrat adéquat. La sélection du contrat est basée sur un ensemble de critères tout en considérant la contrainte du budget disponible. Ensuite, afin d’améliorer la procédure proposée, nous avons proposé des outils d’aide à la décision multicritère pour le choix adéquat d’une stratégie de maintenance. Pour l’étude de la criticité des équipements médicaux et le choix de la maintenance, sept critères ont été étudiés en proposant un couplage de l’approche AHP « Analytical Hierarchy Process » à la technique TOPSIS « Technique for Order Performance by Similarity to Ideal Solution ». Comme les experts du service de maintenance présentaient une certaine incertitude dans leurs jugements, nous avons intégré l’évaluation linguistique floue dans l’étude de la criticité des équipements et dans la sélection de la stratégie de maintenance (Fuzzy AHP couplée avec Fuzzy TOPSIS). Un modèle mathématique MILP a été développé pour la définition des limites de la criticité afin de caractériser les trois stratégies de maintenance. Le bon choix de ces limites permet d’optimiser le coût de la maintenance en respectant le budget disponible. Enfin, un deuxième modèle mathématique MILP a été développé en se basant sur l’heuristique proposée. Ce modèle permet de sélectionner pour chaque équipement, la stratégie de maintenance, internaliser ou externaliser la maintenance et le type du contrat tout en considérant le budget disponible et la charge/capacité du service maintenance / The hospital is a world that is both sensitive and complex, sensitive because the human life is involved and complex because medical facilities are growing in number and in technical complexity. Then, the problem of the medical equipment maintenance in order to keep them in safe, reliable and with high level of availability has become a major preoccupation of the hospital. The objective of this thesis is to provide tools to help the biomedical maintenance service of the hospital to make decisions that allow a better control of costs, while ensuring patient and user safety and maintaining optimal performance of medical equipment. First, a heuristic has been proposed for the choice of internalization or outsourcing maintenance and for the selection of the appropriate contract. The selection of the contract is based on a set of criteria while considering the available budget constraint. Then, to improve the proposed procedure, we proposed multi-criteria decision-making tools to select the appropriate maintenance strategies. Seven criteria have been designed to study the criticality of medical equipment and the choice of maintenance by providing a coupling of the AHP approach "Analytical Hierarchy Process" with TOPSIS technique "Technique for Order Performance by Similarity to Ideal Solution." As the expert judgments of the maintenance department presented some uncertainty, we integrated the fuzzy language assessment of the criticality of the equipment and the selection of the maintenance strategy (Fuzzy AHP coupled with Fuzzy TOPSIS). A mixed integer linear programming model (MILP) was developed to define thresholds of criticality to characterize the three maintenance strategies. According to these thresholds, maintenance cost can be optimized within the available budget. Finally, a second mixed integer linear programming model (MILP) was developed based on the proposed heuristic. This model allows selecting for each equipment, the maintenance strategy, the internalization or the outsourcing of the maintenance and the type of contract while considering the available budget and the workload / capacity of the maintenance department

Rapporten baseras på en litteratur- och intervjustudie kring underhållsstrategier och komponentutbyten i kärnkraftverk, med fokus på komponenter som tenderar till att påverkas av åldring i en högre grad. Exemplifiering sker genom en kompletterande fallstudie kring kabel- och rörgenomföringar av typen Brattbergare som har packbitar bestående av ett polymert material. Erhållet resultat av litteratur- och intervjustudien belyser vilka säkerhetsföreskrifter som råder för all kärnteknisk verksamhet i Sverige. Utöver det erhålls information om hur åldring påverkar ett materials egenskaper över tid och att detta ligger till grund för fastställandet av ett system eller en komponents kvalificerade livslängd. I takt med att majoriteten av världens kärnkraftverk närmar sig sin ursprungligt tilltänkta livslängd och planeras underhållas för fortsatt långtidsdrift finns det ett ökat intresse för effektiva underhållsstrategier. Åldershanteringen har en avgörande roll för anläggningens lönsamhet och driftsäkerhet. Fallstudien föreslår två olika underhållsstrategier som stöds av resultatet av litteratur- och intervjustudien. Deras ekologiska påverkan och ekonomiska omfattning beaktas för att utse den metod som har störst potential att öka resurseffektiviteten och minska kostnaderna för underhållsåtgärder. Vald metod går ut på att praktiska tillståndsmätningar tillämpas för att undersöka hårdheten av packbitar till Brattbergare. Hårdhetsmätningarna syftar till att ge indikationer på i vilken grad packbitarna harpåverkats av degraderande åldringsmekanismer under olika förutsättningar. Resultatet av fallstudien överensstämmer med de resultat som noterades i litteratur- och intervjustudien. Packbitarna hårdnar när de åldras. Två miljöbetingelser som tenderar till att påskynda åldringsprocessen är förhöjda temperaturer och stråldoser. Vald metod för fallstudien är praktiskt realiserbar trots vissa begränsningar i befintliga kärnkraftsanläggningar vid Forsmark. Presenterad strategi bör kunna bistå med en ekologisk och ekonomisk optimering av underhållsarbetet för kabel- och rörgenomföringar. / This report is based on a literature study and interviews regarding maintenance strategies and component replacements in nuclear power plants. Focuses of the study are on components which tend to more commonly be affected by degrading aging mechanisms. Exemplification is done with a complementary case study about cable- and pipe transits with packing pieces made of polymeric materials. A frequently used application for cable- and pipe transits in Swedish NPPs is manufactured by MCT Brattberg AB.  Result obtained from interviews with relevant personnel’s and the literature study providing knowledge about prevailing safety regulations at Swedish nuclear facilities. Moreover, information is gained about how aging affects the features of materials over time and that it is the basis for determining the qualified lifetime of systems and components. Further on this could be of specific interest considering that the majority of the worlds NPPs are close to its intended lifetime and soon entering a phase of LTO. A proper aging management is an important factor when it comes to a safe and reliable operation of an NPP.  The case study compares two different maintenance strategies which are supported by the obtained result from interviews and the literature study. Considering ecological and economic impacts of the strategies, the one with the greatest potential to reduce negative influences are exemplified. Chosen method included practical hardness measurement with a portable durometer at packing pieces for cable- and pipe transits. Measured hardness of the packing pieces indicates at what degree which they have been affected by degrading aging mechanisms given different circumstances.   The obtained result from the two different parts of the report is corresponding to each other. Packing pieces consisting polymers hardens as they age. Elevated temperatures and higher dose rates accelerates the aging process. Represented method of the case study is practically viable at existing NPPs at Forsmark. Presented strategy should be able to assist with an ecological and economic optimization maintenance work for cable- and pipe transits.