Random Maintenance Strategy Modeling of Warranted Products with Reliability Heterogeneity

Using monitored job cycles to design and model random maintenance strategies for ensuring life-cycle reliability has been extensively researched. The reliability heterogeneity over the life cycle has been ignored universally in this type of strategy. In this paper, using two different areas of regions that can screen reliability, two random maintenance strategies were customized for the life-cycle reliabilities of warrantied products with monitored job cycles to be ensured based on reliability heterogeneity. In the case of using minimal repair, the first one was flexibly customized depending on whether the first failure occurs in the region consisting of limited job cycles or a period of warranty service, whichever occurs first. Such a strategy is called flexible repair warranty first (FRWF) and can be used to ensure warranty-stage reliability during a product's life cycle. The FRWF strategy is modeled from the perspectives of cost and time measures. Based on whether the first failure of the product through its FRWF occurs in another region, random periodic replacement (RPR) and classic periodic replacement (CPR) are triggered to customize the second one, which is named bivariate customized random maintenance (BCRM) because two decision variables are considered. The BCRM and its variants are modeled from the perspectives of the average cost rates. Finally, numerical analysis of some of the customized strategies was performed from the numerical perspective. Numerical analysis showed that the presented FRWF is superior to the classic free repair warranty (FRW) strategy because the servicing time of the presented FRWF strategy is longer than the servicing time of the classic FRW strategy at the same cost.