Abstract

In accelerated life testing, the products are tested under high stress conditions and the results are used to draw inferences about the product lifetime under the normal stress condition using a regression model. In this article, optimal k-level constant-stress and step-stress accelerated life tests are compared to the Rayleigh failure data under progressive Type I censoring. The objective is to quantify the advantage of using step-stress testing relative to constant-stress testing. Due to constrained resources in practice, stress durations must be determined carefully at the design stage to run an accelerated life test efficiently. The stress durations directly affect the experimental cost and the estimate precision of the parameters of interest. This article investigates the optimal stress durations based on several (T/C/D/P/R) optimality criteria under the constraint that the total experimental cost does not exceed a prespecified budget. In addition, these criteria are compared together. Under the budget constraint, these two stress loading schemes are compared. Based on the numerical results, the cost constraint reduces cost and time of the test. It is found that the T-optimal design has the lowest cost and time for the unconstrained testing in both stress loading. Finally, a real data set is analyzed for illustrative purposes.

摘要

在加速寿命测试中，对产品在高应力条件下进行测试，并使用回归模型将结果用于推断在正常应力条件下的产品寿命。在本文中，最优k在渐进式I型检查中，将高阶恒压和阶跃应力加速寿命测试与瑞利失效数据进行了比较。目的是量化相对于恒定压力测试而言，使用逐步压力测试的优势。由于实践中资源有限，必须在设计阶段仔细确定应力持续时间，以有效地进行加速寿命试验。应力持续时间直接影响实验成本和目标参数的估计精度。本文根据几个（T / C / D / P / R）最优标准，条件是总实验费用不超过预先指定的预算。另外，将这些标准进行比较。在预算约束下，比较了这两种压力加载方案。根据数值结果，成本约束可以减少测试成本和时间。发现在两个应力载荷下，T最优设计的无约束测试的成本和时间最低。最后，出于说明目的对真实数据集进行了分析。