Sequential Inspection and Maintenance Policy for Multiple Systems with Wiener Degradation Failure under Availability Requirement

Abstract

This paper investigates the sequential inspection and maintenance policy for multiple systems under availability requirement. The state of each system is described by an identical Wiener degradation process with unknown parameters. A system failure is defined by the excess of degradation to certain critical value. The degradation of each system can only be known through non-periodic, discrete time inspection. At each inspection time, preventive maintenance or replacement is carried out considering the degree of system degradation. There are two types of critical values, alarm threshold and failure threshold, both of which are used to determine the maintenance actions combined with the system degradation history. The unknown parameters are sequentially estimated incorporated into the decision making, and then the next inspection time is determined under average availability requirement. Different alarm thresholds are analysed and the proposed inspection and maintenance procedure is illustrated with numerical examples.