Modeling and analysis for multiple stress-type accelerated lifedata

摘要

This paper describes a model for multiple stress-type acceleratedlife data. In addition, the use of an algorithm, which was specificallydeveloped for this model is illustrated. The model is based on thewidely known log-linear model (1990) and is formulated for the Weibulland lognormal distributions for a variety of censoring schemes usinglikelihood theory. An algorithm has been developed for the solution ofthis model, and implemented in a recently released software package,ALTA ProTM, specific to accelerated life data analysis. Thealgorithm has been specifically designed to be very flexible and has thecapability of simultaneously solving for up to eight differentstress-types. The advantage of this formulation is that it combines inone model most of the known life-stress relationships for one or twotypes of stresses (such as the temperature-nonthermal model), as well asthe multivariable proportional hazards model. This yields a singlegeneral likelihood function (for a given distribution) whose solution isindependent of both the chosen life-stress relationship and the numberof stress-types. In addition, this model allows for simultaneousanalysis of continuous, categorical and indicator variables. Thesolution to this model provides the engineers with an opportunity toexpand their selection of types of stresses and test conditions whentesting products