Optimal burn-in policy for mixed population of products under two-dimensional combination warranty

In actual production, the heterogeneity of products is ubiquitous. This article considers a new burn-in model for repairable products sold with a two-dimensional combination warranty . It is assumed that the products are heterogeneous and that all failures during the warranty period are repaired by the minimal repair at subpopulations level. Performance-based and cost-based models are developed to obtain optimal burn-in policies under the non-renewing two-dimensional combination warranty policy, respectively. First, under mild conditions, we show that the optimal burn-in time and the optimal usage rate should be as high as possible, provided that the burn-in time and the burn-in usage rate have the upper bounds. Second, we analyze the influence of incorrect use of the failure rate function instead of the intensity function on performance-based and cost-based models. Finally, we compare the optimal burn-in policies of the two models. One illustrative example and relevant sensitivity analysis are also presented.