1,333 research outputs found

    Assembly and Disassembly Planning by using Fuzzy Logic & Genetic Algorithms

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    The authors propose the implementation of hybrid Fuzzy Logic-Genetic Algorithm (FL-GA) methodology to plan the automatic assembly and disassembly sequence of products. The GA-Fuzzy Logic approach is implemented onto two levels. The first level of hybridization consists of the development of a Fuzzy controller for the parameters of an assembly or disassembly planner based on GAs. This controller acts on mutation probability and crossover rate in order to adapt their values dynamically while the algorithm runs. The second level consists of the identification of theoptimal assembly or disassembly sequence by a Fuzzy function, in order to obtain a closer control of the technological knowledge of the assembly/disassembly process. Two case studies were analyzed in order to test the efficiency of the Fuzzy-GA methodologies

    Selective Disassembly Research

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    This article transforms the disassembly graph model into a disassembly matrix model, and plans the path of selective disassembly by solving the matrix model.By conducting selective disassembly research on key components, a disassembly path is planned. When disassembling key parts, the goal is clear and unnecessary disassembly steps are omitted, greatly shortening the disassembly time and improving disassembly effi ciency.This article presents the results of this study through a case study, proving that the results can transform complex component connection diagrams into matrices, and then plan the disassembly path of key components

    Service-oriented disassembly sequence planning for electrical and electronic equipment waste

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    Disassembly sequence planning plays an important role in the end-of-life treatment of electrical and electronic equipment waste (e-waste). Effective planning methods can improve recovery rates and reduce environmental impacts of e-waste. In previous work, neither mathematical models nor optimization algorithms offered a satisfactory solution for this multi-objective disassembly problem. We present a multi-objective model for the problem and a modified teaching-learning-based optimization (MTLBO) algorithm to find the Pareto-optimal frontier. We use numerical simulations to demonstrate and verify the effectiveness and robustness of the algorithm. To do effective disassembly planning, all the participants in the lifecycle of e-waste should work together. Disassembly and recovery of e-waste involve complex processes across the lifecycle. Information support services, disassembly modeling and optimization services must be integrated using computer networks. We also propose a service-oriented framework to support business integration for the participants in the e-waste lifecycle. Effective and optimized disassembly planning can be achieved by invoking the related distributed services. The proposed framework is a novel e-business application for the end-of-life treatment of e-waste

    Decision makings in key remanufacturing activities to optimise remanufacturing outcomes : a review

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    The importance of remanufacturing has been increasing since stricter regulations on protecting the environment were enforced. Remanufacturing is considered as the main means of retaining value from used products and components in order to drive a circular economy. However, it is more complex than traditional manufacturing due to the uncertainties associated with the quality, quantities and return timing of used products and components. Over the past few years, various methods of optimising remanufacturing outcomes have been developed to make decisions such as identifying the best End-Of-Life (EOL) options, acquiring the right amounts of cores, deciding the most suitable disassembly level, applying suitable cleaning techniques, and considering product commonality across different product families. A decision being made at one remanufacturing activity will greatly affect the decisions at subsequent activities, which will affect remanufacturing outcomes, i.e. productivity, economic performance effectiveness, and the proportion of core that can be salvaged. Therefore, a holistic way of integrating different decisions over multiple remanufacturing activities is needed to improve remanufacturing outcomes, which is a major knowledge gap. This paper reviews current remanufacturing practice in order to highlight both the challenges and opportunities, and more importantly, offers useful insights on how such a knowledge gap can be bridged

    Automatic Disassembly Task Sequence Planning of Aircrafts at their End-of-Life

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    RÉSUMÉ Une prise de conscience des problèmes environnementaux à l'échelle mondiale ainsi que des avantages économiques a stimulé les chercheurs à trouver les possibilités de réutiliser et de recycler les produits en fin de vie. Chaque année plusieurs centaines d'avions atteignent globalement fin de leur navigabilité et doivent être retirés du service actif. De ce fait, une attention accrue est maintenant accordée à la fin de vie des avions. Désassemblage joue un rôle important dans la prise de décision de fin de vie. La faisabilité économique du processus de démontage avec beaucoup d'incertitudes est une préoccupation majeure limitant sa mise en oeuvre dans la pratique de l'industrie. De nombreuses recherches dans le domaine de la planification et des opérations de processus de démontage a été fait, qui visent de plus en plus la faisabilité économique du démontage avec la réduction des temps de démontage de proposer des séquences de démontage optimisées. Par conséquent, ces dernières années, de nombreux chercheurs ont publié des articles sur la planification de la séquence de démontage des produits en fin de vie qui est un problème NP-complet optimisation combinatoire. Néanmoins, il y a eu un peu d'attention à la planification de la séquence de démontage d'avions en fin de vie. Cette thèse aborde la planification de séquence de démontage des pièces réutilisables d'avions en fin de vie avant le démantèlement pour le recyclage. Puisque les composants récupérés vont être utilisés à nouveau, une approche non-destructive tout en respectant les instructions fournies dans le manuel d'entretien d'avion intitulé « Aircraft Maintenance Manuel » (AMM) pour le retrait des pièces est prise en considération. Ordonnancement de désassemblage dans cette recherche ne traite pas le séquençage le démontage des pièces comme dans d'autres études, mais il planifie séquence de tâches de démontage dans l'AMM. Une tâche de démontage consiste combinaison d'opérations pour la préparation du démontage ou le procède de démontage pour un ou plusieurs pièces. Tout d'abord, un modèle de séquençage de démontage est proposé par l'examen structure des tâches de démontage dans l'AMM. Ensuite, un code Matlab est développé qui lit la base de données énuméré des tâches et sous-tâches qui sont acquises à partir de l'AMM et génère la séquence de démontage des tâches et sous-tâches automatiquement en utilisant le modèle proposé. Le code est capable de générer des séquences de désassemblage de tâches pour n’importe quelle pièce sollicitée.----------ABSTRACT An awareness of the world’s environmental problems plus economic benefits has stimulated researchers to seek the opportunities to reuse and recycle end-of-life (EOL) products. Each year hundreds of aircraft globally reach end of their airworthiness and should be withdrawn from active service. Due to this fact, increased attention is now being paid to EOL of aircrafts. Disassembly plays an important role in EOL decision making. The economic feasibility of the disassembly process with lots of uncertainties is a main concern limiting its implementation in industry practice. Many researches in the field of disassembly process planning and operations has been done that aim increasing economic feasibility of disassembly with reducing disassembly times with proposing optimized disassembly sequences. Consequently, in recent years, many scholars have published articles on disassembly sequence planning of EOL products that is a NP-complete combinatorial optimization problem. Nevertheless, there has been a scant attention towards disassembly sequence planning of EOL aircrafts. This thesis addresses disassembly sequence planning of reusable components of EOL aircrafts before dismantling it for recycling. Since retrieved components are going to be used again, a nondestructive approach with respecting all instructions provided in aircraft maintenance manual (AMM) for removal of parts is taken into consideration. Disassembly scheduling in this work does not deal with scheduling disassembly of components as in other works but it schedules sequence of removal Tasks in AMM. A removal task consists combination of operations for preparation of disassembly or process of disassembly for a part or multiple parts. At first, a disassembly sequencing model with considering structure of disassembly tasks in AMM is proposed. Afterwards a Matlab code is developed which reads from enumerated database of tasks and subtasks that are acquired from AMM and generates disassembly sequence of tasks and subtasks automatically using the proposed model. The code is capable of generating disassembly sequences of tasks for any given removal task of solicited part. Finally, a greedy and an adaptive greedy algorithm are proposed to optimize disassembly sequence of tasks with minimizing changes in visited zones of disassembly operations. Results generated in Matlab code, suggests effectiveness of proposed adaptive greedy algorithm
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