Profit analysis of a 2-out-of-2 redundant system with single standby and degradation of the units after repair
- PDF / 384,223 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 30 Downloads / 153 Views
ORIGINAL ARTICLE
Profit analysis of a 2-out-of-2 redundant system with single standby and degradation of the units after repair Jitender Kumar • M. S. Kadyan • S. C. Malik
Received: 5 October 2011 / Revised: 19 July 2012 The Society for Reliability Engineering, Quality and Operations Management (SREQOM), India and The Division of Operation and Maintenance, Lulea University of Technology, Sweden 2012
Abstract The purpose of this paper is to carry out the profit analysis of a three unit redundant system in which two units work in parallel and one unit is kept as spare in cold standby. Each unit has direct complete failure from normal mode. There is a single repairman (called server) who visits the system immediately to do repair, inspection and replacement of the units. The unit does not work as new after repair and so called a degraded unit. The degraded unit at its further failure undergoes for inspection to see the feasibility of its repair. If the repair is not feasible, it is replaced immediately by new unit. The system is considered in up-state if any two of original and/or degraded units are operative. The time to failure, repair and inspection of the units are taken as arbitrary with different probability density functions. By adopting semi-Markov process and regenerative point technique, the results for some measures of system effectiveness are obtained in steady state. Keywords 2-Out-of-2 system Single standby Degradation Inspection Replacement and profit analysis
J. Kumar (&) M. S. Kadyan Department of Statistics & O.R., Kurukshetra University, Kurukshetra, India e-mail: [email protected] M. S. Kadyan e-mail: [email protected] S. C. Malik Department of Statistics, M. D. University, Rohtak, India e-mail: [email protected]
1 Introduction It is proved that parallel redundancy is one of the best method to improve the performance and reliability of systems. Therefore, in recent years, reliability and profit analysis aspects of the systems of two or more units have been examined by the researchers including Nakagawa (1980), Gopalan and Naidu (1982), Singh (1989) and Chander (2005). And, most of these systems have been analyzed under a common assumption that unit works as new after repair. Infect, this assumption cannot be considered always true since the working capability and efficiency of a unit after repair depends more or less on the repair mechanism adopted. And, a unit may have increased failure rate if it not repaired by an expert repairman and so called degraded unit after repair. Chander and Mukender (2009) have discussed reliability and economic measures of a 2-out-of-3 redundant system subject to degradation after repair. In that paper, authors also assumed that repair of the degraded unit at its further is always feasible to the system. However, this assumption is not true many times and it is a known fact that degraded unit can be used further failure up to some extent. And, the degraded unit may be replaced by new one in case of its excessive use and high cost of mainten
Data Loading...
