Reliability, Availability And Maintainability Research Articles

Alternative application of availability and deliverability studies to reduce the energy sectors’ carbon emissions

The objective of the paper is to present the advantages of utilising reliability, availability and maintainability (RAM) studies as a decision-making tool for the deployment of carbon capture and storage (CCS), by providing detailed and quantifiable CCS rates of the analysed design concept. The study used methodology to predict carbon capture rates with high confidence for several compression and dehydration train design concepts. This allowed the operator to make decisions on the most cost-efficient design, while having a confident understanding of the design-specific carbon capture potentials. The most favourable CCS concept was combined with the existing liquefied natural gas plant RAM model and production profile for a detailed analysis of remaining daily carbon dioxide (CO2) venting rates as a result of potential CCS outages. The RAM models are based on generic and proven reliability data and include a level of detail that ensures a very reliable prediction of exact carbon capture rates. Besides analysing and comparing the design concept results as system availability, the CCS concept was analysed for its carbon capture deliverability. This provided the operator with a high confidence of average as well as monthly CO2 capture and venting rates for selected CO2 production profiles. The application of RAM for CCS and other energy sustainability projects has proven to be a powerful tool, allowing operators to make informed decisions towards achieving net-zero efficiency. Providing operators with an accurate and long-term prediction of their carbon footprint, when analysed in combination with their energy portfolio.

PENJADWALAN PERAWATAN NITROGEN AIR COMPRESSOR MENGGUNAKAN METODE RELIABILITY AVAILABILITY DAN MAINTAINABILITY (RAM)

This research aims to increase the reliability and availability of the Nitrogen Air Compressor machine and determine the maintenance schedule for the Nitrogen Air Compressor machine. The method used in this research is the Reliability Availability and Maintainability (RAM) method to determine the level of Reliability Availability and Maintainability on Nitrogen Air Compressor machines to determine more optimal maintenance scheduling. The results of this research showed 4 defects in the Nitrogen Air Compressor units C and D components, namely (1) Filter Dryer (M 580-1) (C) produced a system reliability value of 82.47%, a system maintainability value of 83.00%, and Availability that has been carried out can produce an inherent availability value of 99.67% and an operational availability value of 99.92%. (2) Air Inlet Filter (6.4198.1) (C) produces a system reliability value of 81.31%, a system maintainability value of 83.87%, and Availability that has been carried out can produce an inherent availability value of 99.92% and operational availability value is 99.92%. (3) Oil Filter (6.3464.1) (D) and produces a system reliability value of 81.34%, system maintainability value of 85.49%, and the Availability that has been carried out can produce an inherent availability value of 99.93% and operational availability value is 99.93%. (4) Filter Dryer (M 580-1) (D) produces a system reliability value of 80.%, system maintainability value of 85.49%, and Availability that has been carried out can produce an inherent availability value of 99.93% and an operational availability of 99.93%. From these results it can be concluded that the RAM method can determine more optimal machine maintenance scheduling. Suggestions for companies are that they can implement scheduling using the RAM method.

Development of the Reliability Assurance Program in a Brazilian nuclear power plant subsidized by a Reliability, Availability and Maintainability Model

The main objective of this work is to present a methodology for the development of a Reliability Assurance Program (RAP) specific to a PWR experimental nuclear installation, through the analysis of the installation and the development of a preliminary RAP subsidized by a Reliability, Availability and Maintainability (RAM) model. The study of an evaluation was carried out in the long-term decay heat removal of the studied experimental plant, whose data were used for application of the RAP. The necessary steps for applying the developed RAP are followed, using the data from the assessment of the studied plant, resulting in a list of components of significant risk for the Program, and in the following steps of sending the list to the experts panel, ranking of SSCs by the panel and development of the final list of significant risk SSCs for using the list in the optimization of the plant. The RAP subsidized by a RAM model will be able to work with the logical relationships between each component of the plant for their effects on energy generation and with the quantitative prediction of the magnitude of each contributor to the occurrence of high-level events, and the developed methodology can be applicable throughout the experimental plant. In this way, it will be possible to implement the RAP in the plant, which will provide a structured way to meet the regulatory requirements for its licensing. Also, it will be possible to complement the plant safety analysis report, which must contain the RAP.

RAM Analysis at Gas Turbine Power Plant with Six Sigma Method

The goal of this study is to identify breakdown that has an impact on the gas turbine engine's RAM and Six Sigma level in order to assess how well the gas turbine engine performance through the value of RAM (Reliability, Availability, and Maintainability) and Six Sigma. By gathering, compiling, categorizing, and conducting an analysis of data and information on the utilization of gas turbine engines, based on actual data and information, the descriptive analysis method is used to reveal the availability and performance of gas turbine engines. The findings of the RAM and Six Sigma level are examined utilizing the Pareto chart to identify the most impacted breakdown, the Fishbone diagram for root cause analysis, and the five why analysis approach for improvement suggestions. According to research findings, control system failure, VGV system failure, and load distribution problem have an impact on the RAM and Six Sigma level of two gas turbines. The Root cause of the issue is due to a number of factors, including mostly due to technical issues of unreliable old control system and VGV system design, an incorrect maintenance schedule implementation, an incompetent and ignorant of operator or technician to gas turbine engines.

Research on Maintenance Management of Equipment of Magnetic Resonance Imaging Based on RAM

To optimize the maintenance quality management of MRI equipment and ensure the quality and safety of its clinical use. The data of failure time and repair time of a MRI equipment in three years were collected by magnetic resonance repair report system, and then the reliability, availability and maintainability(RAM) were studied and analyzed. The results of reliability analysis showed that the communication module was the key subsystem of the MRI equipment. The results of usability analysis showed that RF module was a key subsystem of MRI equipment. Maintainability results showed that the proportion of the MRI equipment not fully utilized due to maintenance-related problems was 2.58%. In order to improve the availability of MRI equipment, the maintenance time of MRI equipment should be shortened. RAM-based analysis of MRI equipment can help hospital equipment managers to carry out the work of operation optimization, maintenance strategy formulation and safety management of MRI equipment.

A RAM extension to enhance ship planned maintenance system

ABSTRACT This study develops a knowledge-based planned maintenance system (PMS) supported by reliability, availability and maintainability (RAM) analysis. The system enables maintenance plan revisions based on the data analysis which calculates instant RAM values and predicts the future trends. The visualised data is monitored to support decisions at both the operational and management level. The proposed system is demonstrated with the periodical data of the main engine installed onboard a container ship. Particularly, the data visualization is conducted on fuel injection valves. The results illustrate that the enhanced PMS system adds value to the timely and effective planning of routine and non-routine maintenance tasks onboard ships. Considering the existing potential of PMS applications onboard ships, the RAM analysis provides reasonable contributions to ship engine room crew and technical managers. The further study focuses on developing a maintenance planning app to digitalise the process and to strengthen compliance with ISM Code Clause 10 and TMSA 4A.4 requirements.

RAM analysis of dynamic positioning system: An approach taking into account uncertainties and criticality equipment ratings

Currently, a Dynamic Position (DP) System is commonly used for offshore operations. However, DP failures may generate environmental and economic losses; thus, this paper presents the Reliability, Availability and Maintainability (RAM) analysis for two different generations of DP system (DP2 and DP3) used in drilling operations. In addition to the RAM analysis, the approach proposed herein considers the uncertainties present in the equipment failure data and provides more information about criticality equipment ratings and probability density functions (pdf) of the repair times. The reliability analysis shows that, for 3 months of operation, the total failure probability of the DP2 system is 1.52% whereas this probability for the DP3 system is only 0.16%. The results reveal that the bus-bar is the most critical equipment of the DP2 system, whereas the wind sensor represents the priority equipment in the DP3 system. Using 90% confidence level, each DP configuration was evaluated for a 1-year operation, finding a reliability mean equal to 70.39% and 86.77% for the DP2 system and the DP3 system, respectively. The DP2 system asymptotic availability tends to present a constant value of 99.98% whereas for the DP3 system, it tends to be 99.99%. Finally, the maintainability analysis allows concluding that the mean time for system repair is expected to be 3.6 h. This paper presents a logical pathway for analysts, operators, and reliability engineers of the oil and gas industry.

Reliability, availability and maintainability (RAM) investigation of Load Haul Dumpers (LHDs): a case study

Reliability, availability and maintainability (RAM) investigation of Load Haul Dumpers (LHDs): a case study

RAM (reliability, availability and maintainability) of threshing machine in agriculture

RAM (reliability, availability and maintainability) of threshing machine in agriculture

RAM assessment of the repairable industrial structure with genuine human-mistake working conditions with generalized fuzzy numbers

PurposeThe present paper investigated a skim milk powder production plant with genuine human mistake for analyzing its performance in terms of its reliability, availability and maintainability (RAM) indices along with mean time between failure (MTBF) and expected number of failure (ENOF).Design/methodology/approachIn the proposed work, the generalized fuzzy lambda–tau methodology has been used to carry out the analysis of the repairable structure using the improved arithmetic operations for generalized fuzzy numbers by considering the degree of confidence levels.FindingsRAM indices along with MTBF and ENOF are obtained to increase the quality of skim milk powder manufacturing structures of a dairy plant with genuine human-mistake working conditions.Originality/valueIn the present paper, a mathematical model for a complex industrial system based on fuzzy has been developed. Finally, the results are more realistic and comprehensive for the decision-maker for farther application.

Reliability, availability and maintainability aspects of automobiles

This paper presents a review on the recent advancements in the field of reliability, availability and maintainability (RAM) aspects of automobiles. The available literature is analyzed and categorically segregated by addressing various issues of RAM concerned with automobiles. The literature covered reliability aspects of mechanical, tribological and electrical and electronics elements, both at the system and component levels. An exclusive survey of literature on maintainability and maintenance aspects of automobile systems is included. The availability aspects of automobiles are also covered in detail. The research paper will be useful to researchers, maintenance professionals, academicians, designers and others concerned with automobile engineering field for updating their knowledge and exploring the research avenues in RAM aspects of automobile systems. The future scope of research pertaining to contemporary developments in automobiles, where RAM concepts have a great role, is also narrated in the concluding section.

Reliability, availability and maintainability analysis of a bag production industry based on the six sigma DMAIC approach

PurposeThe purpose of this paper is to implement the six sigma (SS) strategy in a bag sector under actual operating circumstances based on defining-measure-analyze-improve and control (DMAIC). During the project, several statistical tools and methods have been used efficiently to create inferences. Thus, to measure and enhance system efficiency, the author calculate reliability, availability and maintainability (RAM) indices. Based on this research, the author show how the SS method and RAM analysis are very helpful in determining maintenance intervals, as well as in planning and organizing the appropriate maintenance strategy.Design/methodology/approachThis study introduces the step-by-step application of the DMAIC methodology for the identification and reduction of bag production line downtime and examines the present operations management. Thus, statistical techniques are used to analyze the failure and repair database. Pareto analysis, histograms and descriptive statistics at the machine and line-level of the historical data were conducted. Trend and serial correlation testing validated the hypothesis of independence and identical distribution of database was performed. In addition, with their best fit allocation, the RAM of both the bag production line and its machines was estimated at separate mission times.FindingsThe main goals of the applied method are to understand the nature of the downtime patterns and to accurately and quantitatively estimate the RAM characteristics of the bag production system. The assessment defines the production line's critical points, requiring further enhancement through an efficient maintenance approach. Therefore, by improving plant efficiency and safety, the author can decrease unplanned downtime and equipment failures.Originality/valueThis research is expected to serve as an attempt to conduct SS DMAIC methodology through RAM assessment and its impact on system efficiency under actual circumstances. The benefit of the methodology is that the manufacturing process is continuously monitored by suitable indicators, the use of which leads to a continuous improvement cycle.

Reliability, Availability and Maintainability Analysis to Improve the Operational Performance of Soft Water Treatment and Supply Plant

The purpose of this paper is to provide results for reliability, availability and maintainability (RAM) measures to improve the operational performance of a soft water treatment and supply plant (SWTS-Plant) through the illustrative case study. RAM analysis of SWTS plant installed in a high-rise society ABC, Jaipur was performed. The descriptive analysis of time to failure and repair has been made along with trend analysis and goodness-of-fit test. The best fitted distributed and parameters have been identified from the existing theoretical distributions using the maintenance data of ABC plant. Reliability and maintainability measures also calculated for the entire plant. It is observed that (i) the plant availability decline from 97.96% to 92.67% (ii) failures of five subsystems dominant with 81.5 % failures and (iii) average failure rate is 937.4 minutes. This study will be supportive to identify the occurring complications in the plant.

Maintenance management of load haul dumper using reliability analysis

PurposeLoad haul dumper (LHD) is one of the main ore transporting machineries used in underground mining industry. Reliability of LHD is very significant to achieve the expected targets of production. The performance of the equipment should be maintained at its highest level to fulfill the targets. This can be accomplished only by reducing the sudden breakdowns of component/subsystems in a complex system. The identification of defective component/subsystems can be possible by performing the downtime analysis. Hence, it is very important to develop the proper maintenance strategies for replacement or repair actions of the defective ones. Suitable maintenance management actions improve the performance of the equipment. This paper aims to discuss this issue.Design/methodology/approachReliability analysis (renewal approach) has been used to analyze the performance of LHD machine. Allocations of best-fit distribution of data sets were made by the utilization of Kolmogorov–Smirnov (K–S) test. Parametric estimation of theoretical probability distributions was made by utilizing the maximum likelihood estimate (MLE) method.FindingsIndependent and identical distribution (IID) assumption of data sets was validated through trend and serial correlation tests. On the basis of test results, the data sets are in accordance with IID assumption. Therefore, renewal process approach has been utilized for further investigation. Allocations of best-fit distribution of data sets were made by the utilization of Kolmogorov–Smirnov (K–S) test. Parametric estimation of theoretical probability distributions was made by utilizing the MLE method. Reliability of each individual subsystem has been computed according to the best-fit distribution. In respect of obtained reliability results, the reliability-based preventive maintenance (PM) time schedules were calculated for the expected 90 percent reliability level.Research limitations/implicationsAs the reliability analysis is one of the complex techniques, it requires strategic decision making knowledge for the selection of methodology to be used. As the present case study was from a public sector company, operating under financial constraints the conclusions/findings may not be universally applicable.Originality/valueThe present study throws light on this equipment that need a tailored maintenance schedule, partly due to the peculiar mining conditions, under which they operate. This study mainly focuses on estimating the performance of four numbers of well-mechanized LHD systems with reliability, availability and maintainability (RAM) modeling. Based on the drawn results, reasons for performance drop of each machine were identified. Suitable recommendations were suggested for the enhancement of performance of capital intensive production equipment. As the maintenance management is only the means for performance improvement of the machinery, PM time intervals were estimated with respect to the expected rate of reliability level.

Reliability, availability and maintainability analyses for railway infrastructure management

Reliable, available, maintainable and safe operation in railway transportation is significant for passenger and freight transportation. For these reasons, European Union put into practice a standard in 1999 known as EN 50126 to prevent railway accidents and to ensure a high level of safety in railway operations. The EN 50126 standard consists of these following concepts: Reliability, Availability, Maintainability and Safety (RAMS). These concepts are also recognised as RAMS analyses, which enable to do risk analyses to minimise the risks to the acceptable levels. In this study, a model framework including some stages was developed and the Reliability, Availability and Maintainability (RAM) analyses were applied to the railway infrastructure management. In addition, a case study was analysed for Uzbekistan high-speed railways between Tashkent and Sirdaryo train stations. The RAM analysis techniques were used during the analysis stages. The analyses were performed for the track geometry and the each type of railway track components to achieve a reliable, available and maintainable railway infrastructure management.

Reliability, availability and maintainability analysis of a cement plant: a case study

Purpose The demand of cement in India is expected to increase rapidly as the government has been giving immense boost to various housing facilities, infrastructure projects, road networks and railway corridors. One of the ways to meet this rise in the demand of cement is to increase the capacity utilization of the existing cement plants by improving their availability. The availability of a cement plant can be improved by avoiding failures and reducing maintenance time through reliability, availability and maintainability (RAM) analysis of its subsystems. The paper aims to discuss this issue. Design/methodology/approach The data related to time between failure (TBF) and time to repair (TTR) of all the critical subsystems of a cement plant were collected over a period of two years for carrying out RAM analysis. Trend test and serial correlation test were performed on TBF and TTR data to verify whether these data are independent and identically distributed or not. Afterwards, the authors use EasyFit 5.6 professional software to find best-fit distribution of TBF and TTR data and their parameters. The effectiveness of a preventive maintenance policy was evaluated by simulating the real and proposed systems. Findings The results of the analysis show that the raw mill and the coal mill are critical subsystems of a cement plant from a reliability point of view, whereas the kiln is a critical subsystem from an availability point of view. The analysis shows that the repair time of the cement mill should be reduced for improving the availability of the cement plant. The RAM analysis showed that the capacity of the case study company is 17 percent underutilized due to maintenance-related problems and 15 percent underutilized because of management-related problems. Practical implications The study exhibits the usage of RAM analysis in deciding preventive maintenance programs of several cement plant subsystems. Thus, it would serve as a reference for reliability and maintenance managers in deciding maintenance strategies of cement plants as well as in improving their capacity utilization. Originality/value The study exhibits the usage of RAM analysis in deciding preventive maintenance programs of several cement plant subsystems. Even more, using a simulation study, the authors show that preventive maintenance of the cement plant beyond a certain level can be disadvantageous as it leads to an increase in downtime and decrease in availability.

Statistical analysis of failure data for estimating reliability, availability and maintainability of an automated croissant production line

PurposeThe purpose of this paper is to compute reliability, availability and maintainability (RAM) indices to measure and improve the performance of an automated croissant production line under real working conditions. Based on this study, the authors demonstrate how RAM analysis is very useful for deciding maintenance intervals and for planning and organizing the adequate maintenance strategy.Design/methodology/approachThe present work is carried out by analyzing failure and repair data based on statistical techniques. Descriptive statistics of the failure and repair data at workstation and line level were carried out. Trend and serial correlation tests validated the assumption of independence and identical distribution of the failure data were conducted. Moreover, the reliability and maintainability of both the croissant production line and its workstations have been estimated at different mission times with their best fit distribution.FindingsThe main objectives of the applied method are to understand the nature of the failure patterns, and to estimate the reliability and maintainability characteristics of the croissant production system in precise quantitative terms. The analysis identifies the critical points of the production line that require further improvement through effective maintenance strategy.Originality/valueThis study is anticipated to serve as an illuminating effort in conducting a complete RAM analysis and its effect on the performance of the system that works under real conditions. The advantage of the methodology is the continuous monitoring of the production process through appropriate indices, the utilization of which leads to a continuous cycle of improvement.

Combining system-theoretic process analysis and availability assessment: A subsea case study

Hazard identification methods are important tools to verify that the system is able to operate according to specifications under different operating conditions. Unfortunately, many of the traditional methods are not adequate to capture possible dysfunctional behavior of complex systems that involve highly coupled parts, non-linear interactions and software-intensive functionalities. The rather recent method named system-theoretic process analysis (STPA) is one promising candidate to improve the coverage of hazard identification in complex and software-intensive system. Still, there is no guideline for utilizing system-theoretic process analysis output to evaluate the potential of loss, which is important for basis of decision-making about system configuration and equipment selection. The focus of this article is to place an interface between system-theoretic process analysis and reliability, availability and maintainability (RAM) analysis. The approach named STPA-RAM model is proposed to translate feedback control loops into stochastic Petri nets for discrete event simulation. The proposed approach is demonstrated with a simple case related to subsea design concept. The major conclusion is that STPA-RAM model extends the application of system-theoretic process analysis, while also improving and as such reducing completeness uncertainty and model uncertainty, associated with input data and information for reliability, availability and maintainability analysis.

A new fuzzy methodology-based structured framework for RAM and risk analysis

The aim of this paper is to propose a new hybridized framework for analyzing the performance issues of a chemical process plant by utilizing uncertain, imprecise and vague information. In the proposed framework, Fuzzy Lambda–Tau (FLT) approach has been used for computing reliability, availability and maintainability (RAM) parameters of the considered system. Further, for enhancing the RAM characteristics of the system, improved Fuzzy Failure Mode Effect Analysis (FMEA) approach is adopted. Under improved Fuzzy FMEA approach, defined Fuzzy linguistic rating values in the form of triangular and trapezoidal Fuzzy numbers have been assigned by the experts to each risk factor of the listed failure causes. The proposed framework is demonstrated with an industrial application in a chlorine production plant of a chemical process industry. The results show decreasing trend for system availability and deposition of solid Nacl, mechanical failure, corrosion due to wet chlorine, scanty lubrication, improper adsorption and valve malfunctioning are identified as the most critical failure causes for the considered system. A comparative performance analysis between the proposed framework, Fuzzy technique for order of preference by similarity to ideal solution (Fuzzy TOPSIS), Fuzzy evaluation based on distance from average solution (Fuzzy EDAS) and Fuzzy Vlse Kriterijumska Optimizacija I Kompromisno Resenje (Fuzzy VIKOR) are then carried out to show the competence of the proposed framework. It is expected that the analytical results would be highly useful in formulating an optimal maintenance policy for such complex systems and may also be used for improving performance of similar plants.

Investigation of reliability, maintainability and availability of a paper machine in an integrated pulp and paper mill

Continuous production of an integrated pulp and paper mill depends on the availability of paper machines. Reliability and maintainability are essential for accomplishing the availability of paper machines. This study investigates the reliability, availability and maintainability (RAM) characteristics of a 120 tonnes per day paper machine from a paper mill in southern region of India. The paper machine is divided into five subsystems for failure analysis. The data was analyzed for trend and serial correlation tests for validating the inference of independent and identical distribution of failure and repair information before each sub system is best fitted to the theoretical probability distributions. Reliability and maintainability of the paper machine has been evaluated at various times which are useful for establishing the preventive maintenance schedules for improving availability of the paper machine. Wire part is found to be more critical subsystem from all points of view and require improvement by 4% and 1.5% in maintainability and availability point of view. The results of the analysis are presented to maintenance department for their active consideration.Keywords: Paper machine, reliability, maintainability, availability, mean time between failures (MTBF), mean time to repair(MTTR), independent and identically distributed(IID)