Modelling accelerated degradation data using Wiener diffusion with a time scale transformation.
Engineering degradation tests allow industry to assess the potential life span of long-life products that do not fail readily under accelerated conditions in life tests. A general statistical model is presented here for performance degradation of an item of equipment. The degradation process in the model is taken to be a Wiener diffusion process with a time scale transformation. The model incorporates Arrhenius extrapolation for high stress testing. The lifetime of an item is defined as the time until performance deteriorates to a specified failure threshold. The model can be used to predict the lifetime of an item or the extent of degradation of an item at a specified future time. Inference methods for the model parameters, based on accelerated degradation test data, are presented. The model and inference methods are illustrated with a case application involving self-regulating heating cables. The paper also discusses a number of practical issues encountered in applications.
Whitmore
G A
GA
Faculty of Management, McGill University, Montreal, Quebec, Canada.
Schenkelberg
F
F
D004868:Equipment Failure; D015993:Life Tables; D016013:Likelihood Functions; D015233:Models, Statistical; D013997:Time Factors