Optimal system design considering maintenance and warranty

This paper addresses the problem of design for reliability considering operation support factors such as maintenance and warranty. An optimization model is formulated to minimize unit time system life cycle cost subject to reliability requirements. Genetic algorithms are used to solve the optimization problem. The models and algorithms reported can be applied or extended to other reliability based design problems. In this paper we present a study on reliability based design of a series-parallel system considering burn-in, warranty and maintenance. The system failure rate function incorporates three different phases of a product life cycle, namely, infant mortality period, the useful period and the wear out period. The system life cycle cost includes costs of burn-in, warranty, installation, preventive maintenance and minimal repair. Genetic algorithms are used to obtain optimal values of system design, burn-in period, preventive maintenance intervals and replacement time. Three distinct cases representing different failure characteristics are studied to investigate the changes in system design and burn-in period for different lengths of warranty.