共查询到18条相似文献,搜索用时 312 毫秒
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《数学的实践与认识》2015,(8)
研究了两个不同型部件串联带有一个冷贮备部件的可修型冷贮备系统.假定三个部件的工作时间和维修时间均服从指数分布,对部件2的修理是几何维修而对部件1和3的修理则是修复如新,且部件2比部件3有优先使用权和优先维修权.在这些假设下,运用补充变量法与几何过程理论,得出了系统可靠度,首次故障前平均时间,可用度,瞬时故障频度和修理工空闲的概率等可靠性指标. 相似文献
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管廷禄 《数学的实践与认识》2006,36(8):117-124
考虑了由三个部件和一个维修工组成的线形可修系统.假定可修系统中的三个部件是相互独立的,每个部件的工作时间和维修时间均服从负指数分布.部件故障后不能修复如新以及关键部件具有优先维修权的情形下,利用几何过程与广义马尔可夫过程等数学工具对该系统的可靠性指标进行了深入的研究.我们得到了该系统的瞬时可用度,可靠度的L ap lace变换表达式.从而得到系统的稳态可用度及首次故障前的平均时间.为进一步探索线形可修系统、复杂串并联和复杂并串联系统提供了一条新途径. 相似文献
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《数学的实践与认识》2017,(22)
针对面向多波次飞行任务的机群维修作业调度问题,以装备保障人员、保障时间为主要约束,以非机组保障方式为主要保障方式,以机群最大可用度为目标,用网络流结构模式表述机群处于飞行、停机和修理的流程,建立了机群维修作业的混合整数规划模型,采用分支界定法求解,通过实例分析验证,所建模型和方法可以有效的实现机群维修作业的调度,以满意的人员配置方案满足任务的可用度要求. 相似文献
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本文讨论的带单向关闭规则和多种维修方式的两部件串联可修模型,比许多现有模型更一般。我们用向量马氏过程方法求得了它的可靠度和可用度,在(0,t)中的平均故障次数和平均更新次数。 相似文献
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机会维修策略下的系统可用度分析 总被引:1,自引:0,他引:1
机会维修是针对多部件系统提出的一类新的维修策略,主要解决部件间存在经济相关性的问题.利用更新过程理论建立了机会维修策略下的系统模型,并给出了系统瞬态和稳态可用度的求解方法.通过分析比较可知,利用更新过程稳态下的某些特性,可以不必求解更新方程而比较简便地求解系统稳态可用度. 相似文献
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离散时间单部件可修系统瞬时可用度的渐近稳定性 总被引:1,自引:0,他引:1
针对离散时间下修理有延迟的单部件可修系统,研究了有限时间约束下的系统瞬时可用度模型.证明了该系统瞬时可用度的渐近稳定性,并得到了系统稳态可用度的表达式.结果表明系统瞬时可用度的稳定性对离散时间系统和连续时间系统具有一致性,进一步说明了离散时间下瞬时可用度模型的有效性,同时也加强了研究有限时间段内系统瞬时可用度波动的理论基础. 相似文献
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This article presents an asset management-oriented multi-criteria methodology for the joint estimation of a mobile equipment fleet size, and the maintenance capacity to be allocated in a productive system. Using a business-centred life-cycle perspective, we propose an integrated analytical model and evaluate it using global cost rate, availability and throughput as performance indicators. The global cost components include: (i) opportunity costs associated with lost production, (ii) vehicle idle time costs, and (iii) maintenance resources idle time costs. This multi-criteria approach allows a balanced scorecard to be built that identifies the main trade-offs in the system. The methodology uses an improved closed network queueing model approach to describe the production and maintenance areas. We test the proposed methodology using an underground mining operation case study. The decision variables are the size of a load-haul-dump fleet and specialized maintenance crew levels. Our model achieves savings of 20.6% in global cost terms with respect to a benchmark case. We also optimize the system to achieve desired targets of vehicle availability and system throughput (based on system utilization). The results show increments of 7.1% in vehicle availability and 13.5% in system throughput with respect to baseline case. For the case studied, these criteria also have a maximum, which allows for further improvement if desired. The results also show the importance of using balanced performance measures in the decision process. A multi-criteria optimization was also performed, showing the Pareto front of considered indicators. We discuss the trade-offs among different criteria, and the implications in finding balanced solutions. The proposed analytical approach is easy to implement and requires low computational effort. It also allows for an easy re-evaluation of resources when the business cycle changes and relevant exogenous factors vary. 相似文献
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针对定期检修退化可修系统提出了一种维修更换模型,且假定系统在每个周期中检修时间逐渐递增、检修"修复如旧"和故障维修为"修复非新"时,选择系统的故障次数N为更换策略,利用更新过程和单调的几何过程理论建立数学模型,求出了系统经长期运行单位时间内的期望效益的表达式.最后还对结果进行了讨论,并给出了数值例子验证该方法的有效性. 相似文献
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《European Journal of Operational Research》2006,175(2):821-835
This paper considers a condition-based maintenance model for continuously degrading systems under continuous monitoring. After maintenance, the states of the system are randomly distributed with residual damage. We investigate a realistic maintenance policy, referred to as condition-based availability limit policy, which achieves the maximum availability level of such a system. The optimum maintenance threshold is determined using a search algorithm. A numerical example for a degrading system modeled by a Gamma process is presented to demonstrate the use of this policy in practical applications. 相似文献
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This paper proposes a multi-objective approach to model a replacement policy problem applicable to equipment with a predetermined period of use (a planning horizon), which may undergo critical and non-critical failures. Corrective replacements and imperfect repairs are taken to restore the system to operation respectively when critical and non-critical failures occur. Generalized Renewal Process (GRP) is used to model imperfect repairs. The proposed model supports decisions on preventive replacement intervals and the number of spare parts purchased at the beginning of the planning horizon. A Multi-Objective Genetic Algorithm (MOGA) coupled with discrete event simulation (DES) is proposed to provide a set of solutions (Pareto-optimum set) committed to the different objectives of a maintenance manager in the face of a replacement policy problem, that is, maintenance cost, rate of occurrence of failures, unavailability, and investment on spare parts. The proposed MOGA is validated by an application example against the results obtained via the exhaustive approach. Moreover, examples are presented to evaluate the behavior of objective functions on Pareto set (trade-off analysis) and the impact of the repair effectiveness on the decision making. 相似文献
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A dynamic unreliability assessment and optimal maintenance strategies for multistate weighted k‐out‐of‐n:F systems 下载免费PDF全文
In this paper, a dynamic evaluation of the multistate weighted k‐out‐of‐n:F system is presented in an unreliability viewpoint. The expected failure cost of components is used as an unreliability index. Using failure cost provides an opportunity to employ financial concepts in system unreliability estimation. Hence, system unreliability and system cost can be compared easily in order to making decision. The components' probabilities are computed over time to model the dynamic behavior of the system. The whole system has been assessed by recursive algorithm approach. As a result, a bi‐objective optimization model can be developed to find optimal decisions on maintenance strategies. Finally, the application of the proposed model is investigated via a transportation system case. Matlab programming is developed for the case, and genetic algorithm is used to solve the optimization model. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献