Optimal minimal maintenance of deteriorating system subject to exponential failures with maintenance and repair of general distributions
The article presents a model of multistage degraded system subject to minimal maintenance, random failures and partial repairs. Constant state dependent transition rates for the degradation failure processes are considered while the minimal maintenance and the partial repairs follow general distributions with square of coefficient of variation less than or equal to one and state dependent which are more realistic and can be modelled by hypoexponential or Erlang distributions to use the Markovian property. The objective of the article is to calculate the steady state availability of the system, and the optimal mean time to minimal maintenance maximising the availability in case of state independent Erlang and deterministic distributions .This article extends previous results that can be considered as particular cases of this one. Numerical examples are provided to illustrate applicability of the expressions that are obtained throughout the article.