Joint optimal periodic and conditional maintenance strategy

Abstract

Purpose In this paper, an optimal periodic replacement strategy is proposed. This strategy suggests new items to perform replacements at failure. Preventive replacements, scheduled at instants kT ( k =1, 2,…) are carried out only if the item's age exceeds a threshold to be determined. Parameters T and b are derived from an optimization model aiming to maximize the steady state availability under budgetary constraints or to minimize the expected total cost per unit of time over an infinite horizon, while the steady state availability must be higher than some given threshold. Costs and durations associated with replacement actions are supposed to be known. Design/methodology/approach Employs mathematical models to investigate the expected cost rate and the steady state availability with illustrative examples. Findings Analytical and numerical results have been obtained for a system whose lifetime is distributed according to an Erlang distribution. Practical implications The proposed strategy seems more efficient than the basic block replacement strategy aiming to maximize the steady state availability. It is also easy to implement. Originality/value This new strategy would appear to be more efficient than the previous basic block replacement strategy.