Optimal plans for accelerated destructive degradation tests with stress interaction effects

Accelerated destructive degradation tests (ADDTs) have been devised to obtain reliability informations regarding highly reliable products that do not survive the measurement process. Majority of existing ADDT models consider independent effects of various stress factors, ignoring their possible interactions. Various studies in engineering evident that these interactions significantly affect the degradation process. This article introduces an ADDT framework to study the effect of multiple stress factors and their interactions on a product’s life. The degradation process is formulated using Wiener process and a generalized log-linear (GLL) stress–life relationship. The estimates of the model parameters and quantile lifetimes are obtained using approximation as well as numerical methods. Optimal test plans are obtained under D-optimality and V-optimality criteria. Simulation study is carried out for numerical illustrations, and a real data set concerning the thermal damage in a sandstone is analyzed. Robustness of the proposed model is examined under stress-dependent diffusion parameter.