Optimum Step-Stress Accelerated Life Tests With Competing Causes of Failure under Exponential Distribution

In this paper, we consider the optimum time-step and failure-step stress accelerated life tests with competing causes of failure, which life of each failure cause is assumed to be exponential. We obtain the optimum test designs to minimize the sum of asymptotic Variance the Maximum Likelihood Estimation （MLE） of the log mean life in each cause at a design stress. We generalize a number of results, which are shown in other papers ago.