Adaptive condition-based maintenance decision framework for deteriorating systems operating under variable environment and uncertain condition monitoring
Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability
The present article deals with the efficient use of different types of monitoring information in optimizing condition-based maintenance decision making for a deteriorating system operating under variable environment. The degradation phenomenon of a system is the fatigue crack growth that is modeled by a physics-based stochastic process. The environment process is assumed to be modeled by a time-homogenous Markov chain with finite state space. We suppose that the environmental condition is observed perfectly, while the crack depth can be assessed imperfectly through a non-destructive ultrasonic technique. As such, two kinds of indirect information are available on the system at each inspection time: environmental covariate and diagnostic covariate. Based on this set of information, two condition-based maintenance strategies adaptive to environmental conditions are developed. In the first one, the adaptation scheme is time-based, while in the second, it is condition-based. These maintenance strategies are compared one with another and to a classical non-adaptive one to point out the performances of each adaptation scheme and hence the appreciation of using different information sources in maintenance decision making.