No / This paper studies the selective maintenance problem for multi-state series systems working in variable loading conditions in the next mission. In the mission, a component's degradation depends on its current state and the load applied on it. A load-dependent degradation model is proposed for multi-state components operating in variable loading conditions. This model is inspired by the load-sharing model where many components share a common workload and the failure rate of a component depends on the state of other components. A Monte-Carlo simulation method is presented to simulate the multi-state component's degradation and to evaluate the system reliability. The final objective is to determine the best selective maintenance strategy to maximize the expected system reliability in the next mission within available resources. An illustrative example, reliability estimation results, and analysis of optimal selective maintenance scenarios for different levels of budget limitation are provided.

No / This paper studies the selective maintenance problem for multi-state systems with structural dependence. Each component can be in one of multiple working levels and several maintenance actions are possible to a component in a maintenance break. The components structurally form multiple hierarchical levels and dependence groups. A directed graph is used to represent the precedence relations of components in the system. A selective maintenance optimization model is developed to maximize the system reliability in the next mission under time and cost constraints. A backward search algorithm is used to determine the assembly sequence for a selective maintenance scenario. The maintenance model helps maintenance managers in determining the best combination of maintenance activities to maximize the probability of successfully completing the next mission. Examples showing the use of the proposed method are presented.

L’objectif de cette thèse est de construire un framework qui représente les incertitudes aléatoires et épistémiques basé sur les approches probabilistes et des théories d’incertain, de comparer les méthodes et de trouver les propres applications sur les grands systèmes avec événement rares. Dans la thèse, une méthode de normalité asymptotique a été proposée avec simulation de Monte Carlo dans les cas binaires ainsi qu'un modèle semi-Markovien dans les cas de systèmes multi-états dynamiques. On a aussi appliqué la théorie d’ensemble aléatoire comme un modèle de base afin d’évaluer la fiabilité et les autres indicateurs de performance dans les systèmes binaires et multi-états avec technique bootstrap. / Our research objective is to build frameworks representing both aleatory and epistemic uncertainties based on probabilistic approach and uncertainty approaches and to compare these methods and find the proper applicatin for these methods in large scale systems with rare event. In this thesis, an asymptotic normality method is proposed with Monte Carlo simulation in case of binary systems as well as semi-Markov model for cases of dynamic multistate system. We also apply random set as a basic model to evaluate system reliability and other performance indices on binary and multistate systems with bootstrap technique.

Les switches multimodulables sont des systèmes qui, sous l'action d'un ou de plusieurs stimuli extérieurs, donnent naissance à un ensemble d'états aux propriétés physico-chimiques différentes. Au cours de cette thèse, plusieurs voies de synthèse permettant l'obtention d'une nouvelle famille de biphotochromes organiques constitués d'un dithiényléthène relié à une indolino[2,1-b]oxazolidine ont été mises au point. Les dithiényléthènes préparés présentent d'excellentes performances photochromiques et s'interconvertissent de façon réversible entre deux états stables thermiquement. Les 10-styryl-indolino[2,1-b]oxazolidines sont des molécules acidochromiques et doublement photochromiques par ouverture du cycle oxazolidine ou isomérisation de la double liaison. Ce système moléculaire compte jusqu'à huit états multicolores aux propriétés physico-chimiques différentes, accessibles par irradiations lumineuses et variation de l'acidité. Les propriétés ont été étudiées en solution et en matrice polymère, tous les états des biphotochromes étant caractérisés par spectroscopie d'absorption électronique et RMN. Cette thèse a été l'occasion de développer le premier système multimodulable incorporant huit états différents au sein d'une même molécule. / Multi-addressable switches are systems that give rise to a set of states with different physical-chemical properties upon the effect at least one external stimulus. During this thesis, several synthetic routes to a new family of organic biphotochromes composed of a dithienylethene linked to an indolino[2,1-b]oxazolidine have been developed. Synthesized dithienylethenes exhibit excellent photochromic properties and can be reversibly photoswitched between two thermally stable states. 10-styryl-indolino[2,1-b]oxazolidines are acidochromic molecules and photochromic by opening of the oxazolidine ring or cis/trans isomerization of the double bond. This molecular system exhibits up to eight multicoloured states with different physical-chemical properties, interchangeable by different sequences of light irradiation and pH variation steps. Properties were studied in solution and in a polymer matrix and all biphotochromes states have been characterised by electronic absorption spectroscopy and NMR. Additionally, the first multi-addressable system incorporating eight different states within the same molecule is described.