Cost‐effective degradation test plan for a nonlinear random‐coefficients model

The determination of requisite sample size and the inspection schedule considering both testing cost and accuracy has been an important issue in the degradation test. This paper proposes a cost‐effective degradation test plan in the context of a nonlinear random‐coefficients model, while meeting some precision constraints for failure‐time distribution. We introduce a precision measure to quantify the information losses incurred by reducing testing resources. The precision measure is incorporated into time‐varying cost functions to reflect real circumstances. We apply a hybrid genetic algorithm to general cost optimization problem with reasonable constraints on the level of testing precision in order to determine a cost‐effective inspection scheme. The proposed method is applied to the degradation data of plasma display panels (PDPs) following a bi‐exponential degradation model. Finally, sensitivity analysis via simulation is provided to evaluate the robustness of the proposed degradation test plan.