Modeling random warranty and replacement strategies for products with two modes of failure and mission cycles

Characteristics like mission cycle, failure number, and failure mode act as crucial metrics for evaluating the reliabilities of products subject to various failure modes. As a result, this study develops two distinct strategies to manage product reliabilities. The first strategy focuses on managing warranty-stage reliability and employs renewable-free replacements to enhance warranty appeal. Using either the criterion of "whichever occurs first" or "whichever occurs last", this strategy is called a three-dimensional random warranty-first-or-last approach with renewable-free replacement. The second strategy involves various replacements, providing comprehensive management of post-warranty reliability. The first approach within this second type of strategy is called the bivariate random periodic replacement-first-with-corrective-replacement method. The proposed warranty can identify reliability heterogeneities, which serves as the basis for adapting the second approach within the second type of strategy. Time and cost factors are used to quantify the proposed strategies. Numerical analyses are carried out focusing on key parameters.