Availability optimization of a series system with multiple repairable load sharing subsystems considering redundancy and repair facility allocation

• Published in: International journal of system assurance engineering and management 2013-09, Vol.4 (3), p.262-274
• Main Authors: Arabi, Ali A. Yahyatabar, Jahromi, A. Eshraghniaye
• Format: Article
• Language: English
• Subjects: Engineering; Engineering Economics; Logistics; Marketing; Organization; Original Article; Quality Control; Reliability; Safety and Risk
• ISSN: 0975-6809; 0976-4348
• DOI: 10.1007/s13198-013-0182-5

Redundancy technique is considered as a way to enhance the reliability and availability of a system. This paper models availability of a repairable system with multiple subsystems in which the involved components follow the load sharing strategy. In redundancy allocation problems, the redundancy level is just considered, whereas, in this paper, the number of repair facility (repairman) is added to the decision variables. The goal is to find the optimal number of repairmen and redundant components in each subsystem for optimization of availability subject to weight, cost and volume constraints. The main contribution of this study is to present a straightforward model for availability optimization of a series system with multiple load sharing subsystems. Two types of decision variables (i.e., redundancy level and the number of repairmen) are directly located into objective function. The proposed model belongs to nonlinear programming. Due to complexity of the objective function, it is very severe to code the model in typical applications such as GAMS or LINGO. A particle swarm optimization algorithm is proposed to solve the problems related to the model. Finally, computational results of three assumed cases with various subsystems are illustrated to prove the efficiency of the proposed algorithm.