scholarly journals A Joint Inspection-Based Preventive Maintenance and Spare Ordering Optimization Policy Using a Three-Stage Failure Process

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-19
Author(s):  
Fei Zhao ◽  
Fengfeng Xie ◽  
Chenghua Shi ◽  
Jianshe Kang
Keyword(s):  
Preventive Maintenance ◽  
Single Unit ◽  
Failure Process ◽  
System State ◽  
Inspection Interval ◽  
Decision Variables ◽  
Construct Optimization ◽  
Joint Policy ◽  
Inspection Policy ◽  
The Times

Separated decision-making for maintenance and spare ordering is unrealistic in the industry, so this paper aims to optimize them together. A joint policy of inspection-based preventive maintenance (PM) and spare ordering considering two modes of spare ordering, namely, a regular order and an emergency order, is proposed for single-unit systems using a three-stage failure process. If the system is recognized to be in the minor defective stage, the original inspection interval is shortened and a regular order is placed. However, replacement is undertaken preventively or correctively if the severe defective stage is identified or a failure occurs. Depending on the system state and the state of the regular ordered spare when replacement is needed, all possible scenarios are considered to construct optimization model I. The decision variables are the optimal inspection interval and the times of shortening the original inspection interval. Additionally, model II on the basis of an assumption that the spare is always ordered at time 0 is also developed. The results from a numerical example illustrated the applicability and the effectiveness of model I compared to model II, and the irregular inspection policy is validated to be cost-saving compared to the regular inspection policy.

A Three-Phase Inspection Policy Based on a Three-Stage Failure Process

2014 ◽  
Vol 488-489 ◽  
pp. 1272-1276
Author(s):  
Wen Bin Wang ◽  
Hui Ying Wang ◽  
Rui Peng
Keyword(s):  
Single Unit ◽  
Cost Model ◽  
Failure Process ◽  
Policy Model ◽  
Numerical Example ◽  
Unit System ◽  
Inspection Interval ◽  
Three Phase ◽  
Inspection Policy ◽  
The Cost

This paper proposes a three-phase inspection policy model based on a three-stage failure process for a single unit system. Different from existing works which usually assume unique inspection interval, the three-phase inspection policy allows the inspection policy to change according to the identified state of the unit. The possible renewal scenarios are considered based on which the cost model is proposed. Numerical example is presented, and the results clearly reveal the advantage of the three-phase inspection policy over the unique interval inspection.

scholarly journals An Enhanced Preventive Maintenance Optimization Model Based on a Three-Stage Failure Process

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Ruifeng Yang ◽  
Jianshe Kang ◽  
Zhenya Quan
Keyword(s):  
Optimization Model ◽  
Preventive Maintenance ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Failure Process ◽  
Maintenance Optimization ◽  
Maintenance Policy ◽  
Model Based ◽  
Inspection Interval

Nuclear power plants are highly complex systems and the issues related to their safety are of primary importance. Probabilistic safety assessment is regarded as the most widespread methodology for studying the safety of nuclear power plants. As maintenance is one of the most important factors for affecting the reliability and safety, an enhanced preventive maintenance optimization model based on a three-stage failure process is proposed. Preventive maintenance is still a dominant maintenance policy due to its easy implementation. In order to correspond to the three-color scheme commonly used in practice, the lifetime of system before failure is divided into three stages, namely, normal, minor defective, and severe defective stages. When the minor defective stage is identified, two measures are considered for comparison: one is that halving the inspection interval only when the minor defective stage is identified at the first time; the other one is that if only identifying the minor defective stage, the subsequent inspection interval is halved. Maintenance is implemented immediately once the severe defective stage is identified. Minimizing the expected cost per unit time is our objective function to optimize the inspection interval. Finally, a numerical example is presented to illustrate the effectiveness of the proposed models.

Design and Inspection Policy for Redundant Systems Using Information of Warranty

2005 ◽  
Vol 277-279 ◽  
pp. 226-232
Author(s):  
Jong Hyen Seo ◽  
Seon Ah Roh
Keyword(s):  
Optimal Number ◽  
Expected Cost ◽  
Cost Rate ◽  
Inspection Interval ◽  
Inspection Policy ◽  
Redundant Systems

This paper considers the problem of determining the optimal number of redundant units in redundant systems with random unit failures and warranty. Parallel and k out of n systems are considered. The optimal number of redundant units which minimize the expected cost rate is found and the number is shown to be finite and unique. For given inspection interval before expiration of warranty, the optimal number of redundant units is also obtained. The effects of inspection and the warranty to the optimal number of redundant units are studied.

scholarly journals Cost -Benefit Analysis of a Single-Unit System with Preventive Maintenance and Weibull Distribution for Failure and Repair Activities

2014 ◽  
Vol 10 (2) ◽  
pp. 5-19 ◽  
Author(s):  
Ashish Kumar ◽  
Monika Saini
Keyword(s):  
Preventive Maintenance ◽  
Single Unit ◽  
Failure Time ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Single Server ◽  
Scale Parameters ◽  
Unit System ◽  
Complete Failure ◽  
Replacement Time

Abstract This paper deals with a reliability model developed for a single-unit system which goes for preventive maintenance after a pre-specific time ‘t’ up to which no failure occurs. There is a single server who takes some time to arrive at the system for doing repair activities. The unit does not work as new after repair at complete failure and so called the degraded unit. The degraded unit is replaced by new one after its failure with some replacement time. The failure time, preventive maintenance time, replacement time and repair time of the unit are taken as Weibull distributed with common shape parameter and different scale parameters. The switching devices are perfect. The system is observed at suitable regenerative epochs to obtain various measures of system effectiveness of interest to system designers and operation managers.

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