The Optimum Allocation of Spare Components in Systems

Abstract

This paper considers a system whose components may be divided into two subsystems, each containing components whose lives are exponentially distributed but with different scale parameters. Each system can be assigned a store of replacement spares for failed components. Charts are presented for allocating a fixed number of spare components between the two sub systems to provide maximum reliability over some specified interval of time. Expected life is also taken as a maximand, and a table is given of combinations of spares of each type so as to maximize system life. The effect of non-exponential component densities upon these optimum allocations of components is also discussed.