Preventive maintenance for coherent systems considering postponed replacement

Abstract

One primary objective of reliability engineering is to achieve optimal maintenance of technical systems, which ensures they remain in good operating condition. This paper proposes an age-based preventive optimal maintenance policy for (Formula presented.) -component coherent systems. Under this proposed strategy, the system begins operating at (Formula presented.) and undergoes preventative maintenance (PM) at a time (Formula presented.). If the system fails before (Formula presented.), it will be replaced with a new one. If the system is still functioning at time (Formula presented.), an assessment is made based on the number of failed components to determine whether the system should be replaced or allowed to continue operating. If the number of failures at (Formula presented.) is below a predetermined threshold (Formula presented.), the PM time (Formula presented.) is postponed and a new PM time (Formula presented.) will be scheduled, and the system continues operating in the interval (Formula presented.). Otherwise, the entire system is preventively replaced at (Formula presented.) with a new one. In this scenario, we use a cost function to determine the optimal values of decision variables (Formula presented.), (Formula presented.), and (Formula presented.). To examine the effectiveness of our proposed model, we analyze some examples of coherent systems using graphical and numerical methods. © 2024 John Wiley & Sons Ltd.