TABLE OF CONTENTS When we consider large and complex systems that consist of many kinds of units, we should make only minimal repair at each failure, and make the planned replacement or do preventive maintenance at periodic times. We consider the following replacement policy which is called periodic replacement with minimal repair at failures [1]. A unit is replaced periodically at planned times ? T ( ? = 1, 2, ). Only minimal repair after each failure is made so that the failure rate remains undisturbed by any repair of failures between successive replacements.
This policy is commonly used with complex systems such as computers and airplanes. A practical procedure for applying the policy to large motors and small electrical parts was given in [2]. More general cost structures and several modified models were provided in [3] [4] [5] [6] [7] [8] [9] [10] [11]. On the other hand, the policy regarding the version that a unit is replaced at the Nth failure and ( N ?1)th previous failures are corrected with minimal repair proposed in [12]. The stochastic models to describe the failure pattern of repairable units subject to minimal maintenance are dealt with [13].
This chapter summarizes the periodic replacement with minimal repair based on our original work with reference to the book [1]. In Section 4.1, we make clear the theoretical definition of minimal repair, and give some useful theorems that can be applied to the analysis of...
