Design of an optimal plan of accelerated degradation test via acceleration factor constant principle

Accelerated degradation test (ADT) has been extensively applied to reliability assessment. To improve the efficiency-cost ratio of ADT, the optimal design method of ADT has become a research hot topic. An optimal design method based on acceleration factor, in which a Wiener degradation model and a step-stress ADT were considered, was proposed in the paper. In order to establish an accurate accelerated degradation model, acceleration factor constant principle was applied to derive the changing rules of Wiener process parameters with accelerated stress. Besides, the exact expression of acceleration factor was determined for a Wiener degradation model. The asymptotic variance of acceleration factor, which was considered as a measure of the consistency of failure mechanisms, was selected to be the objective function of optimal problem so as to ensure that the failure mechanism of products under accelerated stresses is probably consistent with that under the normal use stresses. A numerical example of designing an optimal ADT plan for a certain type electrical connector was studied, in which the effectiveness and feasibility of the proposed method were validated.