Preventive Maintenance Program Research Articles

Optimization in Indonesia’s Bridge Preventive Maintenance Programme: A Proposal

This paper proposes optimisation method for the bridge preventive maintenance programme. The main focus is to predict the optimum preventive maintenance period of time - or, interval - so that bridges could be maintained better. A mathematical model has been developed in this study and is approached using the Markov Chain. Other optimisation techniques will also be discussed here and the reason for selecting the Markov Chain other than other current optimisation techniques is presented as well in a convincing argument. Development of software to help apply the devised mathematical model is in-progress and is clearly discussed.

Oral Microbiota, Periodontal Status, and Osteoporosis in Postmenopausal Females.

Alterations in hormone levels during menopause decrease bone density and may worsen oral health, favoring the growth of periodontal pathogens, whose detection could improve the diagnosis of periodontitis. The aim of this study is to detect and quantify the main periodontal pathogens in the oral microbiota of postmenopausal females and to explore the relationship between clinical and periodontal parameters. This was an observational cross-sectional study of 76 postmenopausal females. Dental examinations and sampling for microbiologic evaluation were performed, and a history of osteoporosis/osteopenia was collected. Real-time polymerase chain reaction was used for detecting and quantifying Fusobacterium nucleatum (Fn), Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Campylobacter rectus (Cr), and Tannerella forsythia (Tf). The results obtained were subjected to statistical analyses. Statistical significance was defined as P <0.05. Periodontitis was detected in 77.1% of females with osteoporosis/osteopenia (P >0.05). A significant correlation was found between osteoporosis and missing teeth. T. forsythia and C. rectus were detected in 100% of the samples, Fn and Pg in 98.7%, and Aa in 73.7%. Osteoporosis did not influence the prevalence of periodontitis among postmenopausal females. The presence of periodontopathogenic bacteria was not sufficient to confirm disease. A preventive maintenance program for postmenopausal females, particularly osteoporotic females, who are at greater risk of tooth loss, could minimize the potential effects of bone loss on periodontal tissues.

Study about Improving the Quality Process Performance for a Steel Structures Components Assembly Using FMEA Method

Analysis of failure modes and effects (FMEA) is a method of analyzing the potential failure of a product or process, to develop an action plan aimed at their prevention and increased quality of products, processes and job production environments. As a method of critical analysis, FMEA has very clear objectives aimed at: determination of the weaknesses of a technical system; initiating causes of failure-seeking components; analysis environmental impacts, safety of operation, the product value; provision of corrective actions to remove the causes of the occurrence of defects; provision of a plan to improve product quality and maintenance; determining the needs of technology and modernization of production; increasing the level of communication between departments working people hierarchical levels. FMEA should be used before taking the product. There is no point subsequently, only because customer demands, to achieve FMEA. Therefore, FMEA must be within organizational conduct. Using timely analysis FMEA - Process avoid costly modifications of the technological achievement assembly "stator Housing" by identifying potential defects, avoidance and risk and potential consequences of faults. We studied the potential causes of defects and have proposed improvements. Among these are: implementing and tracking preventive maintenance program; providing specific compliance welding; acquisition of a specialized table seating and download the blank; purchasing a scarfing machine.

Risk-based Maintenance Management of U.S. Public School Facilities

According to the U.S. Department of Education National Center for Educational Statistics (NCES) 1999 report, Condition of America's Public School Facilities, approximately one-quarter of the nation's schools, housing 11 million children, require extensive repair. According to the 2013 ASCE American Infrastructure Report Card, major knowledge gaps exist regarding the current state of our school infrastructure. Funding for school facilities has dropped by 50% since the start of the 2007 recession. The ASCE report emphasizes a need for the development of comprehensive preventive maintenance programs. This paper reviews the literature on risk-based maintenance management and compares this approach to condition-based management systems. The paper further describes an ongoing study to develop and validate a Failure Modes and Effects Analysis (FMEA) system for maintenance management risk analysis for public school facilities.

The present status and future growth of maintenance in US manufacturing: results from a pilot survey.

A research study was conducted (1) to examine the practices employed by US manufacturers to achieve productivity goals and (2) to understand what level of intelligent maintenance technologies and strategies are being incorporated into these practices. This study found that the effectiveness and choice of maintenance strategy were strongly correlated to the size of the manufacturing enterprise; there were large differences in adoption of advanced maintenance practices and diagnostics and prognostics technologies between small and medium-sized enterprises (SMEs). Despite their greater adoption of maintenance practices and technologies, large manufacturing organizations have had only modest success with respect to diagnostics and prognostics and preventive maintenance projects. The varying degrees of success with respect to preventative maintenance programs highlight the opportunity for larger manufacturers to improve their maintenance practices and use of advanced prognostics and health management (PHM) technology. The future outlook for manufacturing PHM technology among the manufacturing organizations considered in this study was overwhelmingly positive; many manufacturing organizations have current and planned projects in this area. Given the current modest state of implementation and positive outlook for this technology, gaps, future trends, and roadmaps for manufacturing PHM and maintenance strategy are presented.

Extending Replacement Intervals of Elastomeric Components by Evaluating Samples Removed From Service

Elastomers play an essential role in pressure vessels as seals, hoses, gaskets, diaphragms, liners, and other critical components. Polymeric materials used for nonpressure applications such as electric power cable insulation have received more attention, with respect to the effects of aging and life management, than critical elastomeric pressure vessel components such as seals. Performance of these seals depends upon the effects of both time- and event-dependent aging. Understanding and addressing aging and degradation are fundamental to effective preventative maintenance and life cycle management programs. Proper management of elastomers is necessary for performance requirements and for cost containment. In one of the case studies presented, synthetic seals in engines were quite costly to change on the suggested OEM (original equipment manufacturer) maintenance schedule, where replacement intervals were based on assumed operating conditions applicable to other industries. When the actual service for these engines is as emergency diesel generators (EDGs, e.g., in nuclear power plants), the use is primarily in stand-by mode, and the usage is far different than that of the manufacturer's target application. In this investigation, the assessment of pressure seal performance was based on situation-specific operation and environmental parameters. This resulted in much longer replacement intervals. In another case study, alternate materials were identified that are expected to improve performance over the original material.

Pulsed Eddy Current Inspection of Support Structures in Steam Generators

Degradation and fouling of support structures in nuclear steam generators (SGs) can lead to SG tube damage and loss of SG efficiency. Inspection and monitoring of support structures combined with preventative maintenance programs can alleviate these effects and extend SG life. Conventional eddy current inspection technologies are extensively used for detecting and sizing indications from wall loss, frets at supports, cracks and other degradation modes in the tubes, as well as assessing the condition of support structures. However, these methods have limited capabilities when more than one degradation mode is present simultaneously, or when combined with fouling. Pulsed eddy current combined with principal components analysis (PCA) was examined for inspection of 15.9 mm (5/ $8^{{\prime }{\prime }}$ ) Alloy-800 tubes and surrounding stainless steel (SS410) support structures. Clear separation of PCA scores associated with tubes from those associated with ferromagnetic SS410 supports permitted measurement of tube-to-support gaps, in either the presence of tube fretting or variation of relative position of the tube within SS410 supports. For concentric tubes, frets could be sized independently of SS410 hole diameter variations, which in other materials could represent support corrosion. Capability to clearly separate scores was attributed to large differences in relaxation times for diffusion of transient fields through the tube compared with diffusion into the ferromagnetic support structure.

Semiparametric Reliability Model in the Failure Analysis of a Coal-Fired Boiler Used in a Thermal Power Plant—A Case Study

ABSTRACTReliability of a system varies under different operating conditions like temperature, humidity, dust, maintenance facilities, maintenance personnel skill, operator skill, etc., called “covariates.” Under poor operating environments the reliability decreases. Therefore, for precise estimation of system reliability, the influence of various covariates is included. This article aims to investigate the effect of five covariates on the reliability characteristics of a coal-fired boiler using the Weibull proportional hazard model, a semiparametric reliability model. The results from the case study indicate that there is a substantial decrease in reliability. A preventive maintenance program based on this calculated reliability will be safer to use.

Managing storeroom operations using cluster-based preventative maintenance

Purpose – The purpose of this paper is to investigate the impact on the cost of materials used to conduct preventive maintenance (PM). The main motivation for this work is to demonstrate how the group technology concept can be used to improve PM operations. In assessing improvement, the impact on the cost of materials used to conduct PM is investigated. Design/methodology/approach – Based on the similarities between machines required maintenance and failure types, machines are grouped together into virtual cells using similarity coefficients. These cells, then, are used to come up with more efficient planning and scheduling procedures to conduct PM operations including inventory of parts and the execution of maintenance operations. Findings – The results demonstrated that the proposed PM approach could provide a significant cost savings over a traditional PM program, especially in industries for which there is considerable material cost for the performance of PM. Originality/value – The results presented in this paper are reliable, objective, and may be expanded by using the same concept of developing virtual cells to group other types manufacturing operations.

Subspace-Based Identification of Acoustic Noise Spectra in Induction Motors

In this paper, we study the identification of acoustic noise spectra in induction motors by using a recently developed frequency-domain cross-power spectrum estimation algorithm. This algorithm is a noniterative high-resolution spectral estimator. In a test rig, from multiple experiments sound data are collected by an array of five-microphones placed hemispherically around motors in a reverberant and noisy room. In order to explore the issue of assembly micromisalignments, each motor is removed from the test rig and then replaced, after which the experiment is then repeated. The identification algorithm is used to detect changes in acoustic noise spectra of induction motors due to mechanical and electrical faults most frequently encountered in industry. Not only the autopower spectra of the individual microphones, but also the cross-power spectra of the microphone pairs are estimated. As a byproduct, it is demonstrated that one microphone is sufficient to identify noise spectra. The estimated acoustic spectra, or more compactly statistics extracted from them, can be used in the development of preventive maintenance programs for induction motors in service.

Optimal decision for warranty with consideration of marketing and production capacity

A successful marketing strategy should be managed to integrate the decisions, such as pricing, post-sale service and production in order to maximise profits but most manufacturers did not fully consider how to integrate them into an effective one in the past. Therefore, in this study, we proposed a mathematical model and a corresponding solution algorithm to assist the decision-makers systematically to decide the synthetic decision. The decision-makers can make warranty and marketing decision according to their production capacity. Besides, the impacts on the profit, the sale, the price and the warranty when the related costs were varying are also discussed in the study, so that the decision-maker can more easily handle the possible situations. The failure times of the product in our study were drawn from a non-homogeneous Poisson process with a specific intensity function (linear, exponential or power law). A preventive maintenance programme was also considered in the warranty policy. Finally, a numerical example was given to demonstrate the effectiveness of the proposed model.

Financial planning for the preventive maintenance of power distribution systems via fuzzy AHP

One of the most important objectives of electricity distribution companies is to improve the reliability of the distribution networks. To this end, the electricity distribution companies try to optimally use the existing financial resources in the planning of preventive maintenance (PM) programs to reduce the imposed costs on the system due to the failure of network components and to improve the network reliability. In fuzzy analytical hierarchical process (fuzzy AHP) method, the degree of network reliability and the effectiveness of PM budget in the improvement of network reliability are selected as decision criteria in the budget allocation procedure. The areas served by the power distribution network are prioritized relative to each other and are assigned weights based on these priorities. The PM budget is determined based on the obtained weights. The medium voltage distribution network of seven areas in the city of Tehran have been selected for the implementation of the proposed method and the analysis of the obtained results. © 2014 Wiley Periodicals, Inc. Complexity 21: 36–46, 2016

Reduction of Stray Losses in Flange–Bolt Regions of Large Power Transformer Tanks

In large power transformers, the presence of stray currents in the structural elements near the high current bushings can be considerable, and this leads to hot spots. This work presents a practical analysis of overheating in the bolts that join the tank and the cover, which are near the high current bushings of the transformer. Overheating results are analyzed and discussed for the case of a 420-MVA transformer. The hot spots in the flange-bolt regions are discovered by thermal maps that are obtained during power transformer operation as a part of a preventive maintenance program. In this paper, we use copper links to ensure the connection of both the cover and tank body, significantly reducing the overheating of the flange-bolt region. The copper link solution has been validated by measurements. We have used calibrated measurement instruments in all the experiments. Moreover, a 3-D finite-element analysis of the geometry of interest has been used to verify the copper link solution.

An Investigation for Prior Failure of Engine Component through Spectroscopy Oil Analysis Program

Monitoring the condition of the engine through oil analysis will help operators to get the most value from their equipment and their lubricant. This is just one part of an overall Preventive Maintenance (PM) Program. Engine lubricant condition reflects the state of health of engine through its properties. Recognition and analysis of the correlation between engine lubricant system based on the lubricant properties and engine performance is crucial to provide insight into engine health. Aim of this paper is an investigation for prior failure of engine component through oil analysis. Engine is the heart of automobile vehicles. Engine performances are directly dependent upon the health of its components like piston, cylinder, cylinder head, crankshaft, cam shaft, connecting rod etc. Metals in lubricating oil can come from various sources, such as wear, contamination and additives. Wear metals result from friction or corrosion of the engine components; for example pistons, bushing, piston ring and bearings, during operation. Contamination can come from dirt, leaks or residual metal pieces. Additives used as detergents, anti-oxidants and anti-wear agents, are added in order to reduce engine wear. Wear of a specific component is heralded by an increase in the concentration of a particular metal, or the sudden appearance of a metal. Since different engine components are composed of different alloys, the increase of a particular metal can be used to identify impending failure of a specific component. An analysis of trace metals in engine oil has permitted the identification of wearing components before severe failure, without dismantling of the engine. Spectrometric Oil Analysis Program (SOAP). The determination of Al, Cd, Cr, Cu, Fe, Mg, Ni, Pb, Sn and Zn impurities using flame atomic absorption spectroscopy method. The used engine oil samples were digested with HCL

Understanding Infrared Windows and Their Effects on Infrared Readings

The use of infrared (IR) windows in electrical control and distribution equipment has become increasingly more prevalent over recent years. With increased focus on electrical safety and the widespread adoption by industry of NFPA-70E, IR systems are increasingly more popular. However, using IR windows with thermal imaging cameras introduces a serious problem when it comes to predictive maintenance, i.e., measurement accuracy. This paper discusses the effects of various materials used in IR windows for noncontact temperature measurement. Varying degrees of measurement inaccuracy and methods to correct for these inaccuracies with various thermal imagers is covered. Other factors outlined will include the factors affecting IR transmission through various IR window materials used in various practical electrical inspection applications. Moreover, how these various materials affect the accuracy of the readings and ways to correct these various transmission losses will be also addressed. The conclusions provide the details for a successful preventive and predictive maintenance program when using various thermal imagers along with different types of IR windows.

Maintenance Plan for a Fleet of Rotary Drill Rigs/Harmonogram Utrzymania I Konserwacji Floty Obrotowych Urządzeń Wiertniczych

Abstract In this paper a basic methodology was used for the reliability modeling and developing a maintenance program for a fleet of four drilling rigs. Failure and performance data was collected from Sarcheshmeh Copper Mine in Iran for a two-year period. Then the available data was classified and analyzed and reliability of all subsystems and whole rigs were modeled and studied. The failure data showed that, in all rigs, electrical, hydraulic and drilling systems are the most frequent failing subsystems of the machine. The reliability analysis showed that transmission system is the most reliable subsystem in all studied rigs. In order to calculate the reliability of whole fleet, it was assumed that operation of at least two drilling rigs is essential for satisfying the production goals. Therefore, probabilistic possibility of all fleet’s states were calculated. In this paper, 80% is selected as the desired level of reliability for developing of preventive maintenance program for each subsystem of the drilling rigs. Finally, the practical approaches were suggested for improving the maintenance operation and productivity of the studied fleet.

Prediction of failure probability of oil wells

We consider parametric accelerated failure time models with random effects to predict the probability of possibly correlated failures occurring in oil wells. In this context, we first consider empirical Bayes predictors (EBP) based on aWeibull distribution for the failure times and on a Gaussian distribution for the random effects.We also obtain empirical best linear unbiased predictors (EBLUP) using a linear mixed model for which the form of the distribution of the random effects is not specified. We compare both approaches using data obtained from an oil-drilling company and suggest how the results may be employed in designing a preventive maintenance program.

Improvement of Preventive Maintenance Plan for an Automatic Labeling System: A Case Study of a Carbonated Soft Drink Industry

The aims of this research are to improve the preventive maintenance plan and to prepare the autonomous maintenance plan of an automatic labeling system for a carbonated soft drink industry as a case study. The labeling system of the case study has experienced the wastes in maintenance. According to the maintenance problem analysis, the main causes are lack of or inadequate preventive maintenance program, inadequate work order monitoring system, and inadequate staff skills (problem-solving skills of maintenance) to perform work. Therefore, in order to reduce the number and length of machine breakdowns and the seriousness of breakdowns, the preventive maintenance program is used instead of breakdown and routine maintenance by which maintenance skills are required, and in order to improve how machines are operated and handled by improving the skills, and the autonomous maintenance manual is set up to prepare for autonomous maintenance. After the improved preventive maintenance plan has been developed and then implemented, it was found that machine downtime reduced by 1.35% and machine availability increased by 1.74%.

Using dogs to detect hidden corrosion

Dogs used as detectors in remote scent tracing (RST) technology usually detect the presence of explosives or contraband in scent samples collected by sucking air from containers or air freight. In this study, five dogs were trained to detect corrosion under the insulation (CUI) of pipes in scent samples collected at a gas processing plants. CUI is a major problem in oil and gas processing plants, causing safety risks and leading to production loss. Scent samples were made by sucking air through drain plugs in the insulation material surrounding the pipes onto filters. During a two year project, dogs trained to detect corrosion using insulation material collected earlier from other corroded locations at the plant were able to detect corrosion on the filters collected from intact insulated pipes at that plant at the same level of proficiency, detecting corrosion at around 59% while producing on average less than 3% false alarms. The systematic training approach, the integration of field samples into training runs and the use of several dogs to improve the reliability of the system are described. Preliminary results on double blind samples were promising: the sensitivity of the detection of field samples was 92%, and the selectivity 93%. The application of such a system as a tool in a preventive maintenance program at oil and gas processing plants could be useful to determine timing of maintenance, thus allowing a more efficient allocation of costly resources necessary for the customary visual inspection.

Performance and Benefits of Michigan Department of Transportation's Capital Preventive Maintenance Program

The Michigan Department of Transportation's (DOT) pavement preservation program dates back to 1992. In Michigan, pavement preservation is implemented primarily through the Michigan DOT's capital preventive maintenance (CPM) program, in which preventive maintenance treatments are used to protect existing pavement surfaces, to slow deterioration, and to correct surface deficiencies. An overall objective of the CPM program is to postpone major rehabilitation and reconstruction activities by extending the service life of pavements. Results of a study performed to calculate the benefits and costs of various preventive maintenance treatments used in the Michigan DOT's CPM program are presented. With benefit defined as the percentage increase in performance over a do-nothing or untreated pavement performance curve where data were available, benefits were calculated for preventive maintenance treatments. Benefit–cost ratios were calculated by unit cost, and permitted the comparison of the cost-effectiveness of similar treatments. The overall performance of the Michigan DOT's CPM program was also examined by comparing the life-cycle costs of a rehabilitation strategy to a preservation strategy with the use of a simplified approach. The outcome showed that the preservation strategy resulted in agency cost savings of approximately 25% per lane mile over a rehabilitation-only strategy. Findings from this study can be used to help the Michigan DOT improve its CPM project selection, treatment selection, and performance monitoring and modeling practices.