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The purpose of this paper is to evaluate various reliability measures like availability, reliability, mean time to failure and profit function.

The authors present a novel method for availability analysis of an engineering system incorporating waiting time to repair. The considered system consists of two subsystems, namely, A and B connected in series. The subsystem B has two identical units in standby arrangement. Each unit of the subsystem has two modes, i.e. normal efficiency or failed. The two standby units of the subsystem B are connected by an imperfect switching. The system is analyzed by supplementary variable technique, Laplace transformation and Gumbel-Hougaard family of copula.

Numerical examples with a way to highlight the important results have been appended at last. Numerical calculation shows that availability and reliability of the system is decreasing with respect to time when failure rates are fixed at different values. Finally, cost analysis of system reveals that the expected profit decreases with increase in service cost.

This paper presents a mathematical model in which an important aspect of switching has been taken into consideration, which is consistent with actual failures of switching by assuming two different types of failure between adjacent transition. It is evaluated with the help of the Gumbel-Hougaard family of copula.

A newly developed model for performing reliability and availability analysis of mechanical devices subject to multiple failure modes is presented. Using this model, reliability analyses of mechanical devices such as brakes, bearings, engines, fans, gears, generators, heat exchangers and pumps are developed. Real life failure rate data for these devices are obtained from various sources and are used in their reliability analyses. Principal failure modes of these devices are identified and expressions for reliability, state probabilities, mean time to failure and variance of time to failure are developed. For known field failure data reliability and state probability plots are shown.

Presents five newly developed models for a Triple Modular Redundancy system having zero, one, two, three, and N voters. Expressions for reliabilities and mean time to failure with and without repair are developed. The plots for state probabilities, reliabilities and mean time to failure are shown.

This paper presents reliability and availability analyses of a robot‐safety system having one robot and n‐redundant safety units with common‐cause failures. The system failure rates and the partially failed system repair rates are assumed constant, and the failed system repair time is assumed arbitrarily distributed. Markov and the supplementary variable methods were used to perform mathematical analysis of this model. Generalized expressions for state probabilities, system availabilities, reliability, mean time to failure, and variance of time to failure are developed. Some plots of these expressions are shown.

This paper aims to investigate the lubrication regime in spherical pump, especially under different structural parameters and operational conditions.

A ball-on-plane configuration is adopted to represent the contact model between spherical piston and cylinder cover. The governing equations, which include the Reynolds and elasticity equations, are solved and validated by Jin–Dowson model. Both minimum film thickness and lambda ratio (ratio of minimum fluid film thickness to combined surface roughness of the piston and cylinder cover) of the equivalent model are obtained using an established model.

The results indicate that piston diameter and radial clearance are the two main factors affecting the pump lubrication regime. Other related parameters such as rotation speed of the piston, load, viscosity of working medium, material matching and surface roughness of piston and cylinder cover also have different impacts on the lubrication regime of the spherical pump.

These results emphasize the importance of the design and manufacturing parameters on the tribological performance of spherical pumps and these are also helpful in improving the spherical pump lubrication regime and enlarging its life cycle. This is to certify that to the best of the authors’ knowledge, the content of this manuscript is their own work. This manuscript has only been submitted to this journal and never been published elsewhere. The authors certify that the intellectual content of this manuscript is the product of their own work and that all the assistance received in preparing this manuscript and sources has been acknowledged.

This paper presents the results of a survey of Canadian robot users concerning robot reliability and safety. Data on 26 questions were analyzed and the resulting findings are presented in the form of tables, histograms, pie charts, etc. Provides conclusions including the fact that approximately 75 per cent of companies are using robots for commercial purposes; most general types of robots used in industry are intelligent robots; frequently ineffective maintenance manuals are provided by the robot manufacturers; and robot‐related problems are generally less than 50 per year.

This article presents four newly developed mathematical models representing non‐maintained parallel systems with hardware failures, common‐cause failures and human error. The Markov method was used to develop expressions for parallel system state probabilities, system reliability and mean time to failure (MTTF). System reliability and MTTF plots are shown. These plots clearly show the effect of common‐cause failures and human error on system reliability.

Presents two models. Model I deals with some characteristics of a single unit system with a sensing device and two types of repairmen. The unit is attached to a sensing device which completely monitors the operating or non‐operating status of the unit. The regular repairman is always available with the system and inspects the operation of the sensing device. If the device is not working, then an expert repairman is called to the system and the operational status of the unit is now monitored by the expert repairman. It is assumed that the failure of the unit, repair of the regular, expert and the status of the sensing device are stochastically independent random variables each having an arbitrary distribution. Several important results have been derived including profit with some applications. In model II, a two‐unit cold standby system with pre‐inspection is considered. In this model, first the regular repairman inspects every unit that fails to ascertain whether he is able to repair it or not. If he can repair it, he proceeds; otherwise an expert repairman is called. An analytical approach to find the optimum interchanging time of units by giving rest to the operative unit is obtained.

While increased mechanization and automation make considerable contributions to mine productivity, unexpected equipment failures and imperfect planned or routine maintenance prohibit the maximum possible utilization of sophisticated mining equipment and require significant amount of extra capital investment. Traditional preventive/planned maintenance is usually scheduled at a fixed interval based on maintenance personnel's experience and it can result in decreasing reliability. This paper deals with reliability analysis and prediction for mining machinery. A software tool called GenRel is discussed with its theoretical background, applied algorithms and its current improvements. In GenRel, it is assumed that failures of mining equipment caused by an array of factors (e.g. age of equipment, operating environment) follow the biological evolution theory. GenRel then simulates the failure occurrences during a time period of interest based on Genetic Algorithms (GAs) combined with a number of statistical procedures. The paper also discusses a case study of two mine hoists. The purpose of this paper is to investigate whether or not GenRel can be applied for reliability analysis of mine hoists in real life.

Statistical testing methods are applied to examine the similarity between the predicted data set with the real-life data set in the same time period. The data employed in this case study is compiled from two mine hoists from the Sudbury area in Ontario, Canada. Potential applications of the reliability assessment results yielded from GenRel include reliability-centered maintenance planning and production simulation.

The case studies shown in this paper demonstrate successful applications of a GAs-based software, GenRel, to analyze and predict dynamic reliability characteristics of two hoist systems. Two separate case studies in Mine A and Mine B at a time interval of three months both present acceptable prediction results at a given level of confidence, 5 percent.

Potential applications of the reliability assessment results yielded from GenRel include reliability-centered maintenance planning and production simulation.

Compared to conventional mathematical models, GAs offer several key advantages. To the best of the authors’ knowledge, there has not been a wide application of GAs in hoist reliability assessment and prediction. In addition, the authors bring discrete distribution functions to the software tool (GenRel) for the first time and significantly improve computing efficiency. The results of the case studies demonstrate successful application of GenRel in assessing and predicting hoist reliability, and this may lead to better preventative maintenance management in the industry.