Planning Dual-Stress Accelerated Degradation Tests with Random-Effects Wiener Process Models

A common feature observed in many ADTs is unit-to-unit variability, which includes random initial degradation levels and degradation rates, as well as the potentially strong correlation between these two factors – often referred to as the “initiation-growth” correlation. Motivated by a real-world application in optical media, this article investigates the design of ADTs involving single or dual stress variables within a Wiener process framework that accounts for these random effects.

Optimum test plans, in terms of test condition settings and sample allocation, are determined by minimizing the asymptotic variance of the estimated <i>p</i>th quantile lifetime under the normal use condition. For dual-stress ADTs, we propose a splitting strategy that generates statistically equivalent three-point nondegenerate plans by decomposing the lower-stress point of a two-point degenerate plan along an iso-stress direction while preserving its weighted centroid.