scholarly journals Reliability modelling and maintenance policy optimization for a repairable parallel system

2021 ◽  
Author(s):  
Reza Ahmadi ◽  
Shaomin Wu ◽  
Amirhossein Sobhani
Keyword(s):  
Integrated Approach ◽  
Maintenance Policy ◽  
Cost Rate ◽  
Preventive Replacement ◽  
State Process ◽  
Reliability Modelling ◽  
Proposed Model ◽  
Average Cost Rate ◽  
Policy Optimization ◽  
Hidden Failures

This paper proposes an integrated approach for reliability modelling and maintenance scheduling of repairable parallel systems subject to hidden failures. The system consists of heterogeneous redundant subsystems whose failures are revealed only by inspections. Inspections at periodic times reveal the components state and repair actions are decided by the excursion of a basic state process describing the total number of failed components in each subsystem. Using the standard renewal arguments, the paper aims at minimizing the average cost rate by the joint determination of the optimal inspection interval, the partial repair threshold and the preventive replacement threshold. We illustrate the procedure for the case as the components' lifetimes conform to the Weibull distribution. Numerical examples are used to illustrate the proposed model and the response of the optimal solutions to the model's parameters.

scholarly journals Reliability modelling and maintenance policy optimization for a repairable parallel system

2021 ◽  
Author(s):  
Reza Ahmadi ◽  
Shaomin Wu ◽  
Amirhossein Sobhani
Keyword(s):  
Integrated Approach ◽  
Maintenance Policy ◽  
Cost Rate ◽  
Preventive Replacement ◽  
State Process ◽  
Reliability Modelling ◽  
Proposed Model ◽  
Average Cost Rate ◽  
Policy Optimization ◽  
Hidden Failures

This paper proposes an integrated approach for reliability modelling and maintenance scheduling of repairable parallel systems subject to hidden failures. The system consists of heterogeneous redundant subsystems whose failures are revealed only by inspections. Inspections at periodic times reveal the components state and repair actions are decided by the excursion of a basic state process describing the total number of failed components in each subsystem. Using the standard renewal arguments, the paper aims at minimizing the average cost rate by the joint determination of the optimal inspection interval, the partial repair threshold and the preventive replacement threshold. We illustrate the procedure for the case as the components' lifetimes conform to the Weibull distribution. Numerical examples are used to illustrate the proposed model and the response of the optimal solutions to the model's parameters.

Sequential imperfect preventive maintenance policy with random maintenance quality under reliability limit

2011 ◽  
Vol 225 (8) ◽  
pp. 1926-1935 ◽  
Author(s):  
Z Wang ◽  
J Yang ◽  
G Wang ◽  
G Zhang
Keyword(s):  
Failure Rate ◽  
Preventive Maintenance ◽  
Average Cost ◽  
Numerical Control ◽  
Maintenance Policy ◽  
Cost Rate ◽  
Proposed Model ◽  
Optimal Maintenance ◽  
Average Cost Rate ◽  
Optimal Maintenance Policy

To determine the optimal maintenance number for a system with random maintenance quality in infinite time horizon, a sequential imperfect preventive maintenance model considering reliability limit is proposed. The proposed model is derived from the combination of the Kijima type virtual age model and the failure rate adjustment model. Maintenance intervals of the proposed model are obtained through an iteration method when both failure rate increase factor and maintenance restoration factor are random variables with a uniform distribution. The optimal maintenance policy is presented by minimizing the long-run average cost rate. A real numerical example for the failures of numerical control equipment is given to demonstrate the proposed model. Finally, a discussion is presented to show how the optimal average cost rate depends on the different cost parameters. The results show that in order to satisfy the practical requirements of high reliability, it is necessary and worthwhile to consider the system's reliability limit in preventive maintenance practice.

Geometric process repair model for an unreliable production system with an intermediate buffer

2016 ◽  
Vol 231 (4) ◽  
pp. 747-759 ◽  
Author(s):  
Guoqing Cheng ◽  
Binghai Zhou ◽  
Ling Li
Keyword(s):  
Production System ◽  
Buffer Stock ◽  
Sensitivity Analyses ◽  
Cost Rate ◽  
Long Run ◽  
Proposed Model ◽  
Joint Policy ◽  
Traditional Assumption ◽  
Average Cost Rate ◽  
Continuous Demand

In this paper, we consider an unreliable production system consisting of two machines (M1 and M2) in which M1 produces a single product type to satisfy a constant and continuous demand of M2 and it is subjected to random failures. In order to palliate perturbations caused by failures, a buffer stock is built up to satisfy the demand during the production unavailability of M1. A traditional assumption made in the previous research is that repairs can restore the failed machines to as good as new state. To develop a more realistic mathematical model of the system, we relax this assumption by assuming that the working times of M1 after repairs are geometrically decreasing, which means M1 cannot be repaired as good as new. Undergoing a specified number of repairs, M1 will be replaced by an identical new one. A bivariate policy [Formula: see text] is considered, where S is the buffer stock level and N is the number of failures at which M1 is replaced. We derive the long-run average cost rate [Formula: see text] used as the basis for optimal determination of the bivariate policy. The optimal policies [Formula: see text] and [Formula: see text] are derived, respectively. Then, an algorithm is presented to find the optimal joint policy [Formula: see text]. Finally, an illustrative example is given to validate the proposed model. Sensitivity analyses are also carried out to illustrate the effectiveness and robustness of the proposed methodology.

scholarly journals A Stochastic Failure Model with Dependent Competing Risks and its Applications to Condition-Based Maintenance

2015 ◽  
Vol 52 (2) ◽  
pp. 558-573 ◽  
Author(s):  
Ji Hwan Cha ◽  
Inma T. Castro
Keyword(s):  
Competing Risks ◽  
Common Source ◽  
Maintenance Strategy ◽  
Failure Model ◽  
Maintenance Policy ◽  
Cost Rate ◽  
Long Run ◽  
Degradation Failure ◽  
Average Cost Rate ◽  
Optimal Maintenance Policy

In this paper a stochastic failure model for a system with stochastically dependent competing failures is analyzed. The system is subject to two types of failure: degradation failure and catastrophic failure. Both types of failure share an initial common source: an external shock process. This implies that they are stochastically dependent. In our developments of the model, the type of dependency between the two kinds of failure will be characterized. Conditional properties of the two competing risks are also investigated. These properties are the fundamental basis for the development of the maintenance strategy studied in this paper. Considering this maintenance strategy, the long-run average cost rate is derived and the optimal maintenance policy is discussed.

A Stochastic Failure Model with Dependent Competing Risks and its Applications to Condition-Based Maintenance

2015 ◽  
Vol 52 (02) ◽  
pp. 558-573 ◽  
Author(s):  
Ji Hwan Cha ◽  
Inma T. Castro
Keyword(s):  
Competing Risks ◽  
Common Source ◽  
Maintenance Strategy ◽  
Failure Model ◽  
Maintenance Policy ◽  
Cost Rate ◽  
Long Run ◽  
Degradation Failure ◽  
Average Cost Rate ◽  
Optimal Maintenance Policy

In this paper a stochastic failure model for a system with stochastically dependent competing failures is analyzed. The system is subject to two types of failure: degradation failure and catastrophic failure. Both types of failure share an initial common source: an external shock process. This implies that they are stochastically dependent. In our developments of the model, the type of dependency between the two kinds of failure will be characterized. Conditional properties of the two competing risks are also investigated. These properties are the fundamental basis for the development of the maintenance strategy studied in this paper. Considering this maintenance strategy, the long-run average cost rate is derived and the optimal maintenance policy is discussed.

Collaborative Optimization of Replacement and Spare Ordering of a Deteriorating System with Two Failure Types

2012 ◽  
Vol 220-223 ◽  
pp. 210-214 ◽  
Author(s):  
Guo Qing Cheng ◽  
Ling Li
Keyword(s):  
Average Cost ◽  
Life Time ◽  
Collaborative Optimization ◽  
Replacement Policy ◽  
Cost Rate ◽  
Ordering Policy ◽  
Long Run ◽  
Proposed Model ◽  
Average Cost Rate ◽  
Optimal Ordering

This paper proposes a model to find optimal ordering and replacement policies for a deteriorating system. Assume that the life time of system has a normal distribution, and it has two failures types, typeⅠfailure is repairable, whereas typeⅡfailure is catastrophic which leads to replacement. A replacement policy N is adopted by which the system will be replaced by an identical new one if available at the time following the Nth typeⅠfailure or the 1st typeⅡfailure whichever occurs first. Furthermore, it considers an ordering policy M in which a spare unit is ordered at the time of the Mth typeⅠfailure or 1st typeⅡfailure, whichever occurs first. The objective is to derive the long-run average cost rate and then find the optimal policy (N,M) such that the average cost rate is minimized. Finally, a numerical example is provided to illustrate the proposed model.

Availability analysis and maintenance optimization for multiple failure mode systems considering imperfect repair

2021 ◽  
pp. 1748006X2110127
Author(s):  
Qingan Qiu ◽  
Baoliang Liu ◽  
Cong Lin ◽  
Jingjing Wang
Keyword(s):  
Failure Modes ◽  
Maintenance Cost ◽  
Imperfect Maintenance ◽  
Maintenance Policy ◽  
Cost Rate ◽  
Availability Analysis ◽  
Long Run ◽  
Optimal Maintenance ◽  
Maintenance Policies ◽  
Periodic Inspections

This paper studies the availability and optimal maintenance policies for systems subject to competing failure modes under continuous and periodic inspections. The repair time distribution and maintenance cost are both dependent on the failure modes. We investigate the instantaneous availability and the steady state availability of the system maintained through several imperfect repairs before a replacement is allowed. Analytical expressions for system availability under continuous and periodic inspections are derived respectively. The availability models are then utilized to obtain the optimal inspection and imperfect maintenance policy that minimizes the average long-run cost rate. A numerical example for Remote Power Feeding System is presented to demonstrate the application of the developed approach.

scholarly journals Adjustment of Maintenance Approach for Improved Operability and Safety of Ship Navigation

2012 ◽  
Vol 22 (2) ◽  
pp. 95-103
Author(s):  
Ante Bukša ◽  
Ivica Šegulja ◽  
Vinko Tomas
Keyword(s):  
Risk Analysis ◽  
Lower Risk ◽  
Risk Index ◽  
Exhaust Valve ◽  
Maintenance Policy ◽  
Proposed Model ◽  
Risk Criterion ◽  
Ship Navigation ◽  
Definition Of ◽  
Navigation Safety

By adjusting the maintenance approach towards the significant components of ship’s engines and equipment, through the use of operational data from the ship machinery’s daily reports, higher operability and navigation safety can be achieved. The proposed maintenance adjustment model consists of an operation data analysis and risk analysis. The risk analysis comprises the definition of the upper and the lower risk criterion, as well as the definition of a risk index. If the risk index is higher than the lower risk criterion, the component is significant, while it is not significant and has an acceptable risk index if the risk index is lower than the lower risk criterion. For each significant component with a risk index found to be “unacceptable” or “undesirable”, an efficient maintenance policy needs to be adopted. The assessment of the proposed model is based on data regarding the power engine original operation throughout a 13-year period. The results of engine failure examinations reveal that the exhaust valve is the most vulnerable component with the highest rate of failure. For this reason the proposed model of adjusting the maintenance approach has been tested on the exhaust valve sample. It is suggested that the efforts to achieve higher ship operability and navigation safety should go in the direction of periodical adjustments of the maintenance approach i.e. choosing an efficient maintenance policy by reducing the risk indices of the significant engine components. KEY WORDS: maintenance adjustment approach, risk analysis, risk index, lower risk criterion, upper risk criterion, significant components, ship navigation

Optimization of Leased Equipment Maintenance Policy Based on History Failure Data

2021 ◽  
pp. 2150030
Author(s):  
Ke Dong ◽  
Kehong Chen
Keyword(s):  
Power Law ◽  
Cost Model ◽  
Maintenance Strategy ◽  
Maintenance Policy ◽  
Power Law Process ◽  
Total Cost ◽  
Cost Rate ◽  
Failure Data ◽  
Expected Total Cost ◽  
The Cost

We propose a maintenance policy for new equipment on a repair-refund maintenance strategy in this paper and derive the optimal lease period from the lessor’s perspective based on independent and identical distribution of historical failure data which obey power law process. The cost model of a full refund and a proportional refund is studied, and the corresponding optimal leasing period is determined by reducing the expected total cost rate to the largest extent. We use a numerical example to illustrate the proposed cost model and analyze the sensitivity of related parameters. Furthermore, we show that the proportional refund policy is preferable than a full refund to the lessor. Finally, according to the simulation outcome, the proposed methods are effective and instructions for lessor in regard to equipment lease are provided.

Condition-based opportunistic maintenance policy for a series–parallel hybrid system with economic dependence

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Aiping Jiang ◽  
Zhenni Huang ◽  
Jiahui Xu ◽  
Xuemin Xu
Keyword(s):  
Hybrid Systems ◽  
Hybrid System ◽  
Maintenance Policy ◽  
Economic Dependence ◽  
Opportunistic Maintenance ◽  
Content Type ◽  
Cost Rate ◽  
Parallel Hybrid ◽  
In Series ◽  
Redundant Structure

PurposeThe purpose of this paper is to propose a condition-based opportunistic maintenance policy considering economic dependence for a series–parallel hybrid system with a K-out-of-N redundant structure, where a single component in series is denoted as subsystem1, and K-out-of-N redundant structure is denoted as subsystem2.Design/methodology/approachBased on the theory of Residual Useful Life (RUL), inspection points are determined, and then different maintenance actions are adopted in the purpose of minimizing the cost rate. Both perfect and imperfect maintenance actions are carried out for subsystem1. More significantly, regarding economic dependence, condition-based opportunistic maintenance is designed for the series–parallel hybrid system: preemptive maintenance for subsystem1, and both preemptive and postponed maintenance for subsystem2.FindingsThe sensitivity analysis indicates that the proposed policy outperforms two classical maintenance policies, incurring the lowest total cost rate under the context of both heterogeneous and quasi-homogeneous K-out-of-N subsystems.Practical implicationsThis model can be applied in series–parallel systems with redundant structures that are widely used in power transmission systems in electric power plants, manufacturing systems in textile factories and sewerage systems. Considering inconvenience and high cost incurred in the inspection of hybrid systems, this model helps production managers better maintain these systems.Originality/valueIn maintenance literature, much attention has been received in repairing strategies on hybrid systems with economic dependence considering preemptive maintenance. Limited work has considered postponed maintenance. However, this paper uses both condition-based preemptive and postponed maintenance on the issue of economic dependence bringing opportunities for grouping maintenance activities for a series–parallel hybrid system.

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