A probabilistic model for maintaining and optimising the life-cycle performance of deteriorating structures

Benefiting from a devised imperfect repair model and given a cost structure, this paper addresses the problem of determining an optimal inspection and threshold-type repair policy for systems whose performance is described by a Wiener process. The system is monitored at periodic times and preventive maintenance actions are carried out in response to the observed system state. The approach can deal with failures defined by performance or regulations. Precisely speaking, failure is defined by a critical set such that the first entry of the performance process to the critical set implies system failure. This approach is typically appropriate for lifecycle models as a specific performance requirement is, or is close to being violated. Since there is a random amount of maintenance, and on the other hand each maintenance incurs a cost, using the renewal-reward theorem, this paper aims at joint determination of an optimal inspection and repair policy providing a right balance between the amount of maintenance and the increasing cost. Benefiting from an imperfect repair model, the presented probabilistic model provides a framework for further developments.