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This paper presents two mathematical models to perform probabilistic safety analysis in maintenance environment. Both models assume system operating in safe and unsafe environments. Model I represents a repairable system with three states: working normally, working in unsafe mode, and failed safely. Model II represents a repairable system with four states: working normally, working in unsafe mode due to human error, working in unsafe mode due to hardware failure, and failed safely. Equations for state probabilities, system availabilities, reliability, and mean time to failure are developed.

The purpose of this paper is to study reliability, availability, and mean time to failure of a repairable robot‐safety system composed of (n−1) standby robots, a safety unit, and a switch.

Generalized expressions for system state probabilities, system availability, reliability, and mean time to failure are developed when the failure rates of robot and safety unit are constant and the failed system repair times are arbitrarily distributed. Supplementary variable and Markov methods were used to develop these expressions.

This study clearly demonstrates that standby robots and the repair process help to improve system availability.

This study will help maintenance engineers and reliability practitioners to become aware of the combined effect of standby robots and the repair process on the performance of the robot‐safety system. Consequently, they will make better maintenance related decisions in organizations such as automobile manufacturers that use robots quite frequently.

This paper has studied the effects of having redundant robots and the repair facilities on the performance of a robot‐safety system with perfect mechanism to turn on a standby robot. This is one of the first attempts to study the combined effects of all these factors on a robot‐safety system.

The purpose of this paper is to review the literature on design for maintainability with emphasis on psychology and cognitive sciences and suggest possible gaps from the point of view of researchers and practitioners.

The paper systematically reviews the published literature and then analyzes it methodically.

The paper discusses a new shift in engineering design, in general, and design for maintainability (DFM) of mechanical systems, in particular.

Literature on DFM of mechanical systems with psychological factors has so far been very limited. This paper reviews a number of papers from the field of mechanical engineering and other related branches of engineering, along with important papers from the field of psychology and cognitive sciences. Subsequently, various merging trends in the field of DFM are identified to help researchers specifying gaps in the literature and direct the research efforts suitably.

The paper contains a comprehensive listing of publications in the field of maintainability from the psychology point of view. The paper will be useful to researchers, designers, maintenance professionals and others concerned with maintainability of a system. This paper is equally useful for the researchers and design professionals from the domain of engineering design irrespective of their field of application.

Resilience as a novel concept has attracted the most attention in the management of engineering systems. The main goal of engineering systems is production assurance and increasing customer satisfaction which depends on the suitable performance of mechanical equipment. “A resilient system is defined as a system that is resistant to disruption and failures and can recover itself and returns to the state before failure as soon as possible in the case of failure.” Estimate the value of the system’s resilience to increase its resilience by covering the weakness in the resilience indexes of the system.

In this article, a suitable approach to estimating resilience in complex engineering systems management in the field of mining has been presented. Accordingly, indexes of reliability, maintainability, supportability, efficiency index of prognostics and health management of the system, and ultimately the organization resilience index, have been used to evaluate the system resilience.

The results of applying this approach indicate the value of 80% resilience if the risk factor is considered and 98% if the mentioned factors are ignored. Also, the value of 58% resilience of this organization’s management group indicates the weakness of situational awareness and weakness in the vulnerable points of the organization.

To evaluate the resilience in this article, five indicators of reliability, maintainability, and supportability are used as performance indicators. Also, organization resilience and the prognostic and health management of the system (PHM) are used as management indicators. To achieve more favorable results, the environmental and operational variables governing the system have been used in performance indicators, and expert experts' opinions have been used in management indicators.

To investigate the optimal burn‐in time from the perspective of minimizing the expected total cost (i.e. manufacturing plus warranty costs) per unit of product sold under a failure‐free renewing warranty policy. The conditions indicating when burn‐in becomes beneficial were also derived.

An age‐dependent general repairable product sold under a failure‐free renewing warranty agreement was considered. In the case of such a general repairable model, there are two ways in which the product can fail: type I failure (minor) can be rectified through minimal repairs; while in type II failure (catastrophic), the product must be replaced. Then optimal burn‐in time is then examined in order to achieve a trade‐off between reducing the warranty cost and increasing the manufacturing cost.

The optimal burn‐in time depends on the failure/repair characteristics, length of warranty, cost parameters and the probability of failure type II (catastrophic). A burn‐in program is beneficial if the initial failure rate is high or product failures during the warranty period are costly. Moreover, the optimal burn‐in time is always less than the infant mortality period.

The product considered in this paper is an age‐dependent general repairable product: on which no such study has yet been conducted. This is also the first study to apply a failure‐free renewing warranty to a general repairable item. It can be seen that the present model is a generalization of the model considered by Chien and Sheu.

Life cycle cost (LCC) analysis is one of the key parameters in designing a sustainable product or system. The application of life cycle costing in the manufacturing industries is still limited due to several factors. Lack of understanding of LCC analysis methodologies is one of the key barriers. This paper presents a generalized framework for LCC analysis of repairable systems using reliability and maintainability principles.

The developed LCC analysis framework and stochastic point processes are applied for the analysis of a typical computerized numerical control turning center (CNCTC) and governing equations for acquisition cost, operation cost, failure cost, support cost and net salvage value are developed. The LCC of the CNCTC is evaluated for the renewal process (RP) and minimal repair process (MRP) approach.

The LCC analysis of the CNCTC reveals that, the acquisition cost is only 7.59% of the LCC, whereas the operation, failure and support costs dominate and contribute nearly 93% of the LCC. The LCC per day for RP requires additional US$ 1.03 than that for MRP. The detailed LCC analysis of the CNCTC identifies the critical components of CNCTC and these components are: spindle motor, spindle motor cooling fan, spindle belt, drawbar, spindle bearing, oil seals, hydraulic hose, solenoid valve, tool holder, lubrication pump motor system, lubrication hose, coolant pump motor system, coolant hose, supply cables, drive battery.

The developed framework of LCC of a repairable system can be applied to any other repairable systems with the appropriate modifications. LCC analysis of CNCTC reveals that the procurement decision of a product or system should be based on LCC and not only on the acquisition cost. The optimum utilization of consumables such as cutting tools, coolant, oil and lubricant can save operation cost. Thus, use of high-efficiency electric motors and the usage of recommended consumables can prolong the life of several components of a system. Therefore, due consideration and attention to these parameters at product design stage itself will decrease failure and support cost and ultimately its LCC.

Presents two newly developed Markov models (I and II) to perform reliability analysis of a system composed of a robot and its associated safety system. Model I presents expressions for robot reliability, mean time between failure, and state probabilities under non‐repairable conditions. Similarly, Model II presents reliability, mean time to failure, and state probability expressions for a repairable robot system. Shows plots for robot system reliability and mean time to failure.

Presents a newly developed stochastic model for performing reliability and availability analyses of a repairable general standby human‐machine system with increasing human error rates and arbitrary failed system repair rates. Also, the model takes into consideration the occurrence of common‐cause failures. The joint‐density function approach, supplementary variable techniques, and linear ordinary differential equation methods were used to perform analyses. Develops the expressions for steady state availability, the system time‐dependent availability, reliability and mean time to failure.

This article surveys the literature dealing with theory and applications of life cycle costing (LCC). It deals with the literature published in the last 25 years and provides 667 references.

The 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).

In 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.

RAM 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.

In 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.