Preventive effect of optimal replacement policies

Purpose: The purpose of this paper is to explore whether or not a preventive replacement model always gives a solution with a specified preventive effect and looks at the relationship between the preventive effect and cost saving. Design/methodology/approach: The age and block replacement policies with the Weibull failure distribution are considered. Measures of the preventive effect associated with specific maintenance policies are derived. Findings: The sufficient condition to achieve a given preventive effect is represented graphically as a function of the system's aging intensity and the cost ratio of failure and preventive replacements. Practical implications: The models developed in the paper will help maintenance engineers to know whether a system is aged or not and then they can make a decision on replacement. Originality/value: The optimal replacement models considered in this paper give a solution with a good preventive effect only if the maintained system is sufficiently aged. The criterion whether or not the system is sufficiently aged is set by the decision-maker based on specific maintenance situations or maintenance objectives.