Estimation of Life Distribution and Maintenance Effect for Repairable Products

Life distribution and maintenance effect of products is the base of maintenance decision. Life data are the sources for estimating life distribution and maintenance effect. In most cases, life data include both corrective maintenance data and preventative maintenance data, so the difficulty is how to get life distribution and maintenance effect of products from these data simultaneously. Considering the maintenance effect is changing with service age, using maximum likelihood estimation method, a likelihood function including both life distribution and maintenance effect of products was built basing on the history maintenance data. At last, estimation values of each parameter were solved by numerical algorithm. The results show that a right estimation of maintenance effect is very important for maintenance decision-making.