The Experts below are selected from a list of 64932 Experts worldwide ranked by ideXlab platform
Christophe Bérenguer - One of the best experts on this subject based on the ideXlab platform.
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optimal buffer inventory and opportunistic preventive Maintenance under random production capacity availability
International Journal of Production Economics, 2008Co-Authors: Romulo I. Zequeira, Jose E Valdes, Christophe BérenguerAbstract:Abstract In this paper we study the determination of the optimal Maintenance policy for a manufacturing facility and the optimal buffer inventory to satisfy the demand during the interruption period due to a Maintenance Action. We consider the possibility of imperfect production and that opportunities for the fabrication of the buffer inventory and opportunities to carry out a Maintenance Action to the production facility are random.
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Periodic imperfect preventive Maintenance with two categories of competing failure modes
Reliability Engineering & System Safety, 2006Co-Authors: Romulo I. Zequeira, Christophe BérenguerAbstract:A Maintenance policy is studied for a system with two types of failure modes: maintainable and non-maintainable. The quality of Maintenance Actions is modelled by its effect on the system failure rate. Preventive Maintenance Actions restore the system to a condition between as good as new and as bad as immediately before the Maintenance Action. The model presented permits to study the equipment condition improvement (improvement factor) as a function of the time of the preventive Maintenance Action. The determination of the Maintenance policy, which minimizes the cost rate for an infinite time span, is examined. Conditions are given under which a unique optimal policy exists.
Nidhal Rezg - One of the best experts on this subject based on the ideXlab platform.
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impact of the corrective Maintenance cost on manufacturing remanufacturing system performance
Modelling Computation and Optimization in Information Systems and Management Sciences, 2015Co-Authors: Sadok Turki, Zied Hajej, Nidhal RezgAbstract:This paper studies a manufacturing remanufacturing system composed by two parallel machines, a serviceable inventory, a remanufacturing inventory and a customer which demands a constant quantity of part. Taking into account the return of the used part and the Maintenance Action, discrete flow model is used to model and to simulate the system. The goal of this work is to evaluate the optimal serviceable inventory level which allows minimizing the sum of inventory, lost sales costs and the corrective Maintenance cost. Numerical results are presented to show the impact of the corrective Maintenance cost on the optimal serviceable inventory level.
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a new inspection heuristic for a condition based Maintenance policy in a spare part returns context
Systems Man and Cybernetics, 2013Co-Authors: Hamza Boudhar, Mohammed Dahane, Nidhal RezgAbstract:In this paper we propose a new heuristic based approach to determine the optimal non-periodic inspection plan on a finite time horizon for a condition-based Maintenance. The considered system consists of a single machine subject to a continuous, monotonous and stochastic degradation which can lead to failure and consequently to a Maintenance Action. The Maintenance Actions consist of replacing the main part of the production unit by another spare part. Spare parts are classified by their degradation into several qualities: New spare parts, which are provided by external supplier with a fixed delivery time. Used spare parts which are collected and provided by the Maintenance service with fixed remanufacturing time, Depending on decision thresholds, the replacement might be either preventive or corrective. The objective is to determine the order/remanufacturing decision threshold (from which an order/remanufacturing is to be launched) and the preventive Maintenance decision threshold to perform the preventive replacement. Our approach aims to minimize the total cost due to replacement, storage, inspection, order/remanufacturing costs and downtime penalty. A simulation-based genetic algorithm is proposed. At the end numerical examples are given to observe the performance of the proposed heuristic.
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effects of extension of subcontracting on a production system in a joint Maintenance and production context
Computers & Industrial Engineering, 2010Co-Authors: Mohammed Dahane, Christian Clementz, Nidhal RezgAbstract:This paper considers the problem of subcontracting constraints under a joint Maintenance management and production control approach. Our objective is to study the effect of an unforeseen extension of subcontracting duration on a production system provider of subcontracting services. We will study a system with a production unit M subject to corrective Maintenance Actions, a result of random breakdowns. We perform a preventive Maintenance Action (PM) for each time T. Corrective and preventive Maintenance have random durations. A buffer stock S with a capacity h, is built up with a production rate U in order to satisfy the constant demand d of the principal costumer, such as U"m"a"x>d. We note @a=U"m"a"x-d, the maximum stock accumulation rate. In addition, the machine M is allocated to perform subcontracting tasks (ST) to a contractor production system, at each moment A"1, for a useful duration A"2, during which it is unavailable for our system. Thus, the machine must satisfy at the same time the constant demand (under a costumer-supplier relationship) and subcontracting tasks (under a contractor-subcontractor relationship). In this context, a mathematical model is developed to determine the impact of an unforeseen extension of subcontracting duration on the generated costs. We will determine the optimal values of T and h and we will discuss the impact of the extension of a ST with @q time units.
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analysis of a production inventory system with randomly failing production unit subjected to a minimum required availability level
International Journal of Production Economics, 2006Co-Authors: Anis Chelbi, Nidhal RezgAbstract:Abstract In this paper, we consider a repairable production unit subject to random failures, which supplies input to a subsequent assembly line. The production unit is submitted to a Maintenance Action as soon as it reaches a certain age ‘T’ or at failure whichever occurs first. A buffer stock ‘h’ is built up in order to guarantee a continuous supply of the assembly line at a constant rate during repair and preventive Maintenance Actions whose respective durations are random. This production unit operating strategy is investigated taking into account a minimum required stationary availability level ‘A’. We find the optimal operating characteristics (h* and T*) which minimize the total average cost per time unit and satisfy the availability constraint.
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modeling and optimizing a joint inventory control and preventive Maintenance strategy for a randomly failing production unit analytical and simulation approaches
International Journal of Computer Integrated Manufacturing, 2005Co-Authors: Nidhal Rezg, Anis ChelbiAbstract:This paper presents a joint optimal inventory control and preventive Maintenance strategy for a randomly failing production unit which supplies an assembly line operating according to a just-in-time configuration. The production unit is submitted to a Maintenance Action as soon as it reaches a certain age T or at failure; whichever occurs first. In order to palliate perturbations caused by breakdowns and by planned Maintenance Actions both with random durations, a buffer stock is built up to ensure the supply of the assembly line at a constant rate. A mathematical model is developed to evaluate the average cost per time unit of the proposed strategy. Due to the complexity of the mathematical model and to some approximation assumptions, a second approach based on simulation and experimental design is developed. It allows us to simulate the proposed policy and to generate a second order response surface for easy computation of the optimal values of the decision variables which are the age T at which prevent...
Michael Pecht - One of the best experts on this subject based on the ideXlab platform.
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development of an optimized condition based Maintenance system by data fusion and reliability centered Maintenance
Reliability Engineering & System Safety, 2010Co-Authors: Bosuk Yang, Michael PechtAbstract:Maintenance has gained in importance as a support function for ensuring equipment availability, quality products, on-time deliveries, and plant safety. Cost-effectiveness and accuracy are two basic criteria for good Maintenance. Reducing Maintenance cost can increase enterprise profit, while accurate Maintenance Action can sustain continuous and reliable operation of equipment. As instrumentation and information systems become cheaper and more reliable, condition-based Maintenance becomes an important tool for running a plant or a factory. This paper presents a novel condition-based Maintenance system that uses reliability-centered Maintenance mechanism to optimize Maintenance cost, and employs data fusion strategy for improving condition monitoring, health assessment, and prognostics. The proposed system is demonstrated by way of reasoning and case studies. The results show that optimized Maintenance performance can be obtained with good generality.
Romulo I. Zequeira - One of the best experts on this subject based on the ideXlab platform.
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optimal buffer inventory and opportunistic preventive Maintenance under random production capacity availability
International Journal of Production Economics, 2008Co-Authors: Romulo I. Zequeira, Jose E Valdes, Christophe BérenguerAbstract:Abstract In this paper we study the determination of the optimal Maintenance policy for a manufacturing facility and the optimal buffer inventory to satisfy the demand during the interruption period due to a Maintenance Action. We consider the possibility of imperfect production and that opportunities for the fabrication of the buffer inventory and opportunities to carry out a Maintenance Action to the production facility are random.
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Periodic imperfect preventive Maintenance with two categories of competing failure modes
Reliability Engineering & System Safety, 2006Co-Authors: Romulo I. Zequeira, Christophe BérenguerAbstract:A Maintenance policy is studied for a system with two types of failure modes: maintainable and non-maintainable. The quality of Maintenance Actions is modelled by its effect on the system failure rate. Preventive Maintenance Actions restore the system to a condition between as good as new and as bad as immediately before the Maintenance Action. The model presented permits to study the equipment condition improvement (improvement factor) as a function of the time of the preventive Maintenance Action. The determination of the Maintenance policy, which minimizes the cost rate for an infinite time span, is examined. Conditions are given under which a unique optimal policy exists.
Tao Yang - One of the best experts on this subject based on the ideXlab platform.
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opportunistic Maintenance for wind turbines considering imperfect reliability based Maintenance
Renewable Energy, 2017Co-Authors: Chen Zhang, Wei Gao, Sheng Guo, Tao YangAbstract:Corrective Maintenance and time-based Maintenance have been widely employed in wind farms. However, the actual Maintenance strategy is much more complex and diverse, and also Maintenance Actions do not always return the system to “as good as new” condition. Moreover, dependencies exist in multi-component systems, and it is more economical to perform preventive Maintenance whenever a repair opportunity presents itself. For an opportunistic Maintenance strategy, when the system is shut down for Maintenance, the Maintenance time of other still functioning parts can be moved up to take advantage of the huge downtime losses. In this paper, an opportunistic Maintenance approach is proposed for wind turbines considering an imperfect Maintenance schedule that is based on reliability. A hybrid hazard rate model is used to describe imperfect Maintenance and explain the effects of corrective Maintenance Action. Comparative examples are used to illustrate the economic advantages of opportunistic Maintenance. Simulation results demonstrate the impact that various Maintenance costs (fixed downtime cost and preventive replacement cost) have on the economic benefit of opportunistic Maintenance strategy. The simulation analysis also provides the optimal opportunistic Maintenance reliability threshold using the fruit fly optimization algorithm to provide guidance for the actual operation and Maintenance of wind farms.
