Optimal Design of Bivariate Step Stress Model For Reliability Prediction Under Type II Censoring

In this paper, we propose an optimization for the simple step stress accelerated life test for two stress variables under type II censoring. The lifetime of the items follows the Gompertz distribution. Furthermore, we model the effects of changing stress as a cumulative exposure function. By minimizing the asymptotic variance of the maximum likelihood estimator of reliability at time ξ, we obtain the optimal bivariate step stress accelerated life test. Finally, the simulation results are discussed to illustrate the effect of the initial estimates on the optimal values