An Opportunity-Based Preventive Replacement Policy of a Single-Unit System

We study a preventive maintenance policy for a system composed of two units, a binary state unit and a three-state unit. Failures of both units are hard and self-announcing. The intermediate, defective state for the second unit can be regarded as a signal of pending failures. Unit 2 is inspected when its age attains integral multiples of interval [Formula: see text] and when unit 1 fails, and preventive replacement is immediate once the defective state is revealed. This strategy could be extended by further providing preventive replacement for the first unit. A case study on an offshore wind turbine is presented for illustration. We find that opportunistic maintenance schemed for both units could effectively reduce the maintenance cost.

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Reliability and Availability Analysis of a Single Unit System with Varying Demand

Mathematical Journal of Interdisciplinary Sciences ◽

10.15415/mjis.2013.21006 ◽

2013 ◽

Vol 2 (1) ◽

pp. 77-88 ◽

Cited By ~ 2

Author(s):

Reetu Malhotra ◽

Gulshan Taneja

Keyword(s):

Single Unit ◽

Availability Analysis ◽

Unit System ◽

Varying Demand ◽

Reliability And Availability

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A Generalized Block Replacement Policy with Minimal Repair and General Random Repair Costs for a Multi-unit System

Journal of the Operational Research Society ◽

10.1038/sj/jors/0420407 ◽

1991 ◽

Vol 42 (4) ◽

pp. 331-341 ◽

Cited By ~ 2

Author(s):

Shey-Huei Sheu

Keyword(s):

Replacement Policy ◽

Minimal Repair ◽

Unit System ◽

Repair Costs

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A weak derivative approach to optimization of threshold parameters in a multicomponent maintenance system

Journal of Applied Probability ◽

10.1017/s0021900200019926 ◽

2001 ◽

Vol 38 (02) ◽

pp. 386-406 ◽

Cited By ~ 1

Author(s):

Bernd Heidergott

Keyword(s):

Optimization Problems ◽

Estimation Algorithm ◽

Replacement Policy ◽

Cost Performance ◽

Weak Derivative ◽

Preventive Replacement ◽

Maintenance System ◽

Threshold Optimization ◽

Age Replacement ◽

The Cost

We consider a multicomponent maintenance system controlled by an age replacement policy: when one of the components fails, it is immediately replaced; all components older than a threshold age θ are preventively replaced. Costs are associated with each maintenance action, such as replacement after failure or preventive replacement. We derive a weak derivative estimator for the derivative of the cost performance with respect to θ. The technique is quite general and can be applied to many other threshold optimization problems in maintenance. The estimator is easy to implement and considerably increases the efficiency of a Robbins-Monro type of stochastic approximation algorithm. The paper is self-contained in the sense that it includes a proof of the correctness of the weak derivative estimation algorithm.

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Optimal repair/replacement policy for a general repair model

Advances in Applied Probability ◽

10.1017/s0001867800010703 ◽

2001 ◽

Vol 33 (1) ◽

pp. 206-222 ◽

Cited By ~ 5

Author(s):

Xiaoyue Jiang ◽

Viliam Makis ◽

Andrew K. S. Jardine

Keyword(s):

Average Cost ◽

Failure Time ◽

Operating Time ◽

Replacement Policy ◽

Repair Cost ◽

Virtual Age ◽

Preventive Replacement ◽

Long Run ◽

Special Cases ◽

Cost Limit

In this paper, we study a maintenance model with general repair and two types of replacement: failure and preventive replacement. When the system fails a decision is made whether to replace or repair it. The repair degree that affects the virtual age of the system is assumed to be a random function of the repair-cost and the virtual age at failure time. The system can be preventively replaced at any time before failure. The objective is to find the repair/replacement policy minimizing the long-run expected average cost per unit time. It is shown that a generalized repair-cost-limit policy is optimal and the preventive replacement time depends on the virtual age of the system and on the length of the operating time since the last repair. Computational procedures for finding the optimal repair-cost limit and the optimal average cost are developed. This model includes many well-known models as special cases and the approach provides a unified treatment of a wide class of maintenance models.

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