Joint Optimization of Condition‐Based Postponed Replacement‐Spare Control Policy with Adaptive Imperfect Inspection for Three‐State System

Inspection‐based replacement and spare provision can balance the residual life utilization as well as failure risk mitigation, thereby enhancing maintenance efficiency through appropriate inspection scheduling. This paper introduces a condition‐based postponed maintenance framework integrating adaptive imperfect inspection and the postponed replacement with dynamic spare provision for a three‐state system. Specifically, (1) a dual‐phase inspection protocol identifies the discrete state with two inspection errors, which adapts to the varying trend of system health condition; (2) the defect reporting triggers an ordinary ordering and preventive replacement renews the system upon the arrival of spare; and (3) a dynamic spare selection mechanism is designed depending on whether no defect reporting occurs prior to the failure. The long‐term operational cost rate serves as the optimization objective involving the cycle lengths of dual‐phase inspection. The superior applicability and effectiveness of the proposed strategy are verified from a case study conducted on a train's bogie axle‐bearings compared with two conventional policies.