Types Of Preventive Maintenance Research Articles

The Influence of Work Zone Management on User Carbon Dioxide Emissions in Life Cycle Assessment on Highway Pavement Maintenance

The higher contribution of traffic delay to environmental impacts is urging the highway agencies to take work zone management into the maintenance schemes decision-making. Aiming to understand the role of work zone management in user CO2 emissions reduction, this paper firstly developed a practical methodological framework of traffic delay-related CO2 emissions caused by highway maintenance based on a popular life cycle user cost analysis approach in regard of the microscopic vehicle operation analysis. The method was applied in an actual freeway flexible pavement with 15-year design life in Shaanxi Province, China, covering three types of preventive maintenance, correction maintenance, and rehabilitation. In addition, the impacts of key inputs of proposed method on work zone user CO2 emissions results were checked. The results show that traffic delay attributes to 29.4% of total CO2 emissions of the life cycle of highway pavement maintenance, and 51.8% of work zone user CO2 emissions result from preventive maintenance, especially from micro vehicle operations including speed change and queue near work zone (62% of total work zone user CO2 emissions). The work zone management alternative strategies related to less traffic volume or higher highway capacity including vehicle type limitation and the limited work zone speed have an advantage in reducing the work zone CO2 emissions over changing work zone length or work zone timing. The findings in this paper may present a useful tool and reference for robustly supporting the decision-making on highway maintenance carbon mitigation in work zone traffic.

PENERAPAN METODE RELIABILITY CENTERED MAINTENANCE ( RCM ) PADA MESIN CAKE BREAKER CONVEYOR DI PABRIK KELAPA SAWIT ( PKS )

Oil palm plantations and their processing units are expected to grow rapidly, advances in science and technology are very fast along with sophisticated equipment created to simplify and speed up a production process in a palm oil factory, one of which is the Cake Breaker Conveyor (CBC) which functions to break/separate oil palm kernels. core of the shell in oil palm kernel processing. Problems that often occur in the process of separating pulp with palm kernel are in the transfer Cake Breaker Conveyor (CBC). This study tries to propose a machine maintenance system using the application of the RCM (Realibility Centered Maintenance) method on the CBC Cake Breaker Conveyor machine, where the RCM (Realibility Centered Maintenance) method is an identification technique with the intention of saving costs and maintenance to minimize the risk and impact of failure. in facilities and equipment utilities. From the test results the Mean Time to Failure (MTTF) value of the CBC engine clutch (Cake Breaker Conveyor) is 1,803 Hours. While the calculation results of the Mean Time to Repair (MTTR) value of the CBC engine clutch (Cake Breaker Conveyor) is 4:00 Hours Types of Preventive Maintenance and Time Based Maintenance For the optimal maintenance interval for the CBC (Cake Breaker Conveyor) engine clutch is 19 days.
 
 Keywords : Cake Breaker Conveyor, Realibility Centered Maintenance, Palm Oil Mill

Practical Queueing Models for Preventive Maintenance Plan Optimization: Multiple Maintenance Types and Numerical Studies

Preventive Maintenance (PM) activities in semiconductor manufacturing are important for equipment availability and reliability. Since PMs are down events that remove a tool from service, when to conduct a PM and how to group multiple PM tasks into shared PM events are key issues. In this article, multiple types of PMs with different intervals are considered in G/G/m failure-prone queueing systems. PMs are classified into two categories: time-based preemptive and time-based non-preemptive. For each category of PM, this article provides PM planning optimization models to seek optimal PM intervals that minimize the mean cycle time of wafer lots. Simulation studies are conducted to explore the performance of the optimization model and the mean cycle time approximations. Moreover, sensitivity analysis is conducted and reveals several properties of the PM planning model. Implementation results are briefly reported for a toolset in semiconductor manufacturing that achieved a 12% reduction in mean cycle time using PM plans based on these modelling approaches.

Sequential imperfect preventive maintenance model with failure intensity reduction with an application to urban buses

Urban buses usually require several distinct types of preventive maintenance. Due to the complexity of urban buses, quantifying the efficiency of preventive maintenance is very important for maintenance management decision-making and optimization. This study presents a sequential imperfect preventive maintenance model to quantify the maintenance efficiency of urban buses. Existing works of sequential imperfect preventive maintenance models are all formulated based on failure intensity reduction. The proposed model in this study defines maintenance efficiency as a proportion of the difference between actual and expected failure intensity increments. Since the proportion of the difference can vary from negative to positive, the proposed model can quantify all kinds of maintenance efficiency given in the existing works. A case study of an urban bus fleet in China is presented to illustrate the effectiveness of the model.

Considerations regarding determination of optimal preventive maintenance periodicity for subsurface sucker rod pumps

The subsurface sucker rod pumps are important equipment used for the secondary oil recovery. In their structure, there are friction couples, which are strongly subjected at wear like barrel-plunger, traveling valve and standing valve. The operating durability of subsurface sucker rod pumps is practically determined by the reliability of these couples depending on the work conditions.The paper presents a case study on the optimization of preventive maintenance of the subsurface sucker rod pumps. The optimal periodicity, of the preventive maintenance of the above mentioned friction couples, is determined on the basis of their operating reliability. There were analyzed two types of preventive maintenance, at fixed time, and at fixed age respectively. The paper results are embodied in practical charts which can be used for choosing optimal preventive maintenance period of the subsurface sucker rod pumps.

Condition-based maintenance policies under imperfect maintenance at scheduled and unscheduled opportunities

Motivated by the cost savings that can be obtained by sharing resources in a network context, we consider a stylized, yet representative, model for the coordination of maintenance and service logistics for a geographic network of assets. Capital assets, such as wind turbines in a wind park, require maintenance throughout their long lifetimes. Two types of preventive maintenance are considered: planned maintenance at periodic, scheduled opportunities, and opportunistic maintenance at unscheduled opportunities. The latter type of maintenance arises due to the network context: When an asset in the network fails, this constitutes an opportunity for preventive maintenance for the other assets in the network. So as to increase the realism of the model at hand and its applicability to various sectors, we consider the option of not-deferring and of deferring planned maintenance after the occurrence of opportunistic maintenance. We also assume that preventive maintenance may not always restore the condition of the system to ‘as good as new.’ By formulating this problem as a semi-Markov decision process, we characterize the optimal policy as a control limit policy (depending on the remaining time until the next planned maintenance) that indicates on the one hand when it is optimal to perform preventive maintenance and on the other hand when maintenance resources should be shared if an opportunity in the network arises. In order to facilitate managerial insights on the effect of each parameter on the cost, we provide a closed-form expression for the long-run rate of cost for any given control limit policy (depending on the remaining time until the next planned maintenance) and compare the costs (under the optimal policy) to those of suboptimal policies that neglect the opportunity for resource sharing. We illustrate our findings using data from the wind energy industry.

Maintenance of generation units coordinated with annual hydrothermal scheduling using a hybrid technique

This paper presents a hybrid technique for solving the generation maintenance scheduling coordinated with middle term hydrothermal dispatch based on the Chu-Beasley genetic algorithm and linear programming. It takes into consideration the non-linearity derived from the cost of the fuel for thermal power plants. The output of the genetic algorithm is a proposal for the start week of the generation maintenance plan that minimises the hydrothermal dispatch cost. This work has two main contributions: on one hand proposing a solution that integrates hydrothermal dispatch and maintenance scheduling in a single model, therefore a new mathematical model and, on the other hand the proposed solution applies a specialised genetic algorithm that has not been applied before to solve this problem. The test system to validate the methodology is composed of three hydro plants and two thermal plants split into 22 generation units, considering three types of preventive maintenance, in a planning term of one year (52 weeks). This methodology combines an exact technique and a specialised genetic algorithm, which favours convergence.

Modeling Failure Process and Quantifying the Effects of Multiple Types of Preventive Maintenance for a Repairable System

In this paper, we consider a repairable system whose failures follow a non‐homogenous Poisson process with the power law intensity function. The system is subject to corrective and multiple types of preventive maintenance. A corrective maintenance has a minimal effect on the system; however, a preventive maintenance may reduce the system's age. We assume the effects of different preventive maintenance on the system are not identical and derive the likelihood function to estimate the parameters of the failure process as well as the effects of preventive maintenance. Moreover, we derive the conditional reliability and the expected number of failures between two consecutive preventive maintenance types. The proposed methods are applied to a real case study of four trucks used in a mining site in Canada. Copyright © 2016 John Wiley & Sons, Ltd.

Imperfect Preventive Maintenance Policy for Complex Systems Based on Bayesian Networks

The main challenge in maintenance planning lies in the realistic modeling of the maintenance policy. This paper is focused on the maintenance optimization of complex repairable systems using Bayesian networks. A new policy is developed for periodic imperfect preventive maintenance policy with minimal repair at failure; this policy allows us to take into consideration several types of preventive maintenance with different efficiency levels. The Bayesian networks are used for complex system modeling, allowing the evaluation of the model parameters. The Weibull parameters and the maintenance efficiency are evaluated thanks to the proposed methodology using Bayesian inference. The approach developed in this paper is applied on a real system, to determine the optimal maintenance plan for a turbo‐pump in oil industry. Copyright © 2016 John Wiley & Sons, Ltd.

Reliability modelling of a parallel system with a supporting device and two types of preventive maintenance

This study presents the reliability assessment of two unit active parallel systems connected to an external supporting device for its operation. The system is under two types of preventive maintenance, online and offline preventive maintenance. The online preventive maintenance (PM) is done before units/system failure while offline preventive maintenance is done to the external supporting device at units'/system failure. Using Kolmogorov forward equations method, explicit expressions related to system effectiveness important to reliability engineers, maintenance managers, system designers, etc. have been obtained. Based on assumed numerical values given to system parameters, graphical illustrations are given to highlight important results. Comparisons are performed to highlight the impact of online and offline preventive maintenance. Reliability of the system is improved with online and offline preventive maintenance.

Models of inspection, routine service, and replacement for a serviceable one-component system

Routine service (RS), inspection manually or aided by condition monitoring and preventive replacement are four types of preventive maintenance (PM) activities often observed in industry, but very few considered to model them together in a maintenance model. This paper proposes such a model for a serviceable one-component system to jointly model the effect of RS and inspection with replacement on the basis of the delay-time concept. The delay-time is a concept that divides a system failure process into two stages: from new until the point of an identifiable defect, and then from this point to failure. The first stage is called the normal stage and the second stage is called the failure delay-time stage. In this paper, we assume RS as the activity which can prolong the normal stage of the system and the replacement as the activity which can renew the system. The replacement could be either failure based or inspection based if the failure delay-time is identified at an inspection. The concept of age reduction is used to model the effect of RS and two inspection models are considered, e.g. without and with condition monitoring. A numerical example is shown to validate the modeling development.

Method for determining optimal power transformers exploitation strategy

The paper suggests a procedure for determining an optimal combination of activities and measures to minimize the expected total costs during the planned exploitation period of power transformers. Combinations of different types of preventive maintenance, spare parts keeping and installation of condition monitoring systems of power transformer individual components are taken into consideration. Power transformer is a complex system, consisting of six components (functional parts). It is assumed that each component has two independent, competing failure modes: a wear-out failure mode, modeled by two-parameter Weibull distribution, and a chance failure mode, characterized by an exponential distribution.The superposition of failures and planned maintenance are taken into account in the analysis of some forms of preventive maintenance. The application of the method suggested and the benefits it provides are demonstrated for one transformer station (TS) 110/10 kV/kV with 2 × 31 500 kVA-110 kV Star-10 kV Delta transformers in case of radial supplying of customers as well as in case when outage of one power transformer does not affect the power supply to customers.

Effect of Type-II and Type-III PMs on Operational Reliability of Buses

This paper deals with modeling the operational reliability of a bus fleet. The operational reliability is represented by the rate of occurrence of minor failures. A power-law failure point process model with the cumulative numbers of type-II and type-III preventive maintenance (PM) as covariates is fitted to a set of real-world data. We evaluate the effect of these two types of PM on minor failures of buses using the fitted model. This provides a method to quantitatively evaluate the effectiveness of a kind of PM actions.

A New Maintenance Strategy of Combining Preventive Maintenance and Opportunistic Maintenance

This paper develops a new preventive maintenance (PM) strategy with opportunistic maintenance (OM) considered for the industries facing the problem of equipment wearing out. All the existing strategies are based on the fixed PM intervals, no matter acquired from the vendor or the optimization results in previous literature. Opportunistic maintenance is known as a good way to reduce the system total down time, but seldom does any paper make the discussion on when and how to conduct it. In the proposed new PM strategy, the flexibility upon the fixed PM interval is introduced. Some types of PM can be postponed, while some can be done in advance. Thus, PM on different components can be combined together to reduce the system down time. Besides, an opportunistic maintenance trigger is considered in this strategy, which can give the engineers an instruction on whether the OM is worth doing for a component when the system is down because of the failure of another component.To evaluate the new PM strategy, we use a 3-component serial system as the case study. The results illustrate that compared with the other existing PM strategies, the proposed strategy is dramatically better with the lowest cost.

Optimal Policies With Decreasing Probability of Imperfect Maintenance

This study applies periodic preventive maintenance to three repair models: major repaired, minimal repaired, or fixed until perfect preventive maintenance upon failure. Two types of preventive maintenance are performed, namely imperfect preventive maintenance, and perfect preventive maintenance. The probability that preventive maintenance is perfect depends on the number of imperfect maintenance operations performed since the last renewal cycle. Mathematical formulas for the expected cost per unit time are obtained. For each model, the optimum preventive maintenance time T/sup */, which would minimize the cost rate, is discussed. Various special cases are considered. A numerical example is presented.

Optimum policies for a system with general imperfect maintenance

This study considers periodic preventive maintenance policies, which maximizes the availability of a repairable system with major repair at failure. Three types of preventive maintenance are performed, namely: imperfect preventive maintenance (IPM), perfect preventive maintenance (PPM) and failed preventive maintenance (FPM). The probability that preventive maintenance is perfect depends on the number of imperfect maintenances conducted since the previous renewal cycle, and the probability that preventive maintenance remains imperfect is not increasing. The optimum preventive maintenance time that maximizes availability is derived. Various special cases are considered. A numerical example is given.

Reliability analysis of a two-unit standby system by computer simulation

We study the two-unit standby system with repair and with preventive maintenance. Preventive maintenance is introduced in order to make the lifetime of the system longer. Using Monte-Carlo method we simulate the work of the two-unit system and we analyze the influence of different types of preventive maintenance on reliability of the system. Monte-Carlo method enables us to find estimates of various parameters relevant to the system for which there exist no explicit formulas in the literature. .

Optimum preventive maintenance for a 2-unit priority-standby system with patience–time for repair

This paper deals with the effect of preventive maintenance (PM) on the reliability measurcs for a 2-unit priority standby system with patience-time for repair. Four types of PM (type (a),(b), (c), and(d)) are considcrcd. Failurc, repair, PM, and replacement time disiributiotls are general whereas delivery time distribution is negative exponential. Regenerative technique in Markov renewal is applied to obtain several reliability characteristics of interest to designers. Finally numerical calculations are given to illustrate the theoretical results

EXPERT-MM: A knowledge-based system for maintenance management

This paper presents an approach to the design and development of knowledge-based systems in general and their application in the field of maintenance management in particular. Our approach is based on the idea that different kinds of knowledge in a given domain, namely declarative, procedural and heuristic are supported by corresponding methods and software tools. A prototype knowledge-based system, called EXPERT-MM, for the maintenance activities in the Siam Gipsum Industry (Bangkok, Thailand) has been worked out as a case study and is described in the paper. EXPERT-MM supports three main functions: maintenance policy suggestions, machine diagnosis and maintenance scheduling. The maintenance policy deals with the three types of preventive maintenance. For each component of the equipment it analyses the historical failure data and recommends an appropriate policy with optimal preventive maintenance intervals. This is based on the experts' knowledge stored in a knowledge base. A rotary screw type air compressor is selected for a diagnosis. The knowledge representation scheme is rule-based and the inference strategy mechanism is backward chaining. The knowledge-acquisition process has been organized and realised using a decision tree diagram. The knowledge base contains 154 rules for the diagnosis and 54 rules for the maintenance model selection. the maintenance scheduling module is procedure based. EXPERT-MM development is based on the software tools dBase III Plus, TURBO PASCAL version 6.0 and expert system shell EXSYS, all integrated into a single software system with a user-friendly interface.

Reliability of a reparable system with preventive maintenance and imperfect switch

A two-unit cold standby redundant system with repair, post-repair, preventive maintenance (PM) and imperfect switchover is considered using three types of PM [types (a), (b) and (c)]. The Laplace transform (LT) of the survivor function (sf) of time to the first system failure (TFSF) and the mean TFSF are derived. A theorem about the effect of PM [type (a)] is proved. Finally numerical calculations are presented to illustrate the results.