Advances in Accelerated Life Tests With Step and Varying Stress

This article describes recently developed methodology useful for planning, modeling, and analyzing life data from accelerated tests with step and varying stresses. The article reviews background on basic accelerated test models and a cumulative damage model. The article presents analyses of residuals to assess the quality of the data and how well such a model fits the data. This article shows how to use accelerated test data to estimate the life distribution of a population in service where units have differing varying stress over time. The article surveys plans for accelerated tests with varying stress.