Estimation of the parameters for a complex repairable system with preventive and corrective maintenance

Estimation of reliability and maintainability parameters is essential to modeling repairable systems and determining maintenance policies. However, this estimation becomes more difficult when system failure times are neither identically nor independently distributed. This is due to the aging of repairable systems under imperfect maintenance. In this paper, reliability and maintainability RAM parameters are estimated in the maximum likelihood sense based on historical RAM data and using the virtual age model of Kijima Type I and Type II. A Weibull distribution for the first system failure is assumed. Kijima Type I and II imperfect corrective and preventive maintenance are also considered. Using the maximum-likelihood approach, four parameters of this repairable system are estimated. The proposed method is illustrated with simulated data.