A Birnbaum-Saunders accelerated life model

The 2-parameter family of probability distributions introduced by Birnbaum & Saunders characterizes the fatigue failure of materials subjected to cycl ic stresses and strains, It is shown that the methods of accelerated life t esting are applicable to the Birnbaum-Saunders distribution for analyzing a ccelerated lifetime data, and the (inverse) power law model is used due to its justification for describing accelerated fatigue failure in metals, Thi s paper develops the (inverse) power law accelerated form of the Birnbaum-S aunders distribution, and explores the corresponding inference procedure-in cluding parameter estimation techniques and the derivation of the s-expecte d Fisher information matrix, The model approach in this paper is different from an earlier work, which considered a log-linear form of a model with ap plications to accelerated life testing. Here, using an example data set, th e fitted model is effectively used to estimate lower distribution percentil es and mean failure times for particular values of the acceleration variabl e. The benefits of having an operable closed form of the Fisher information matrix, which is unique to this article for this model, include interval e stimation of model parameters and LCB on percentiles using relatively simpl e computational procedures.