Time Censored Ramp Test for Weibull Distribution in Stress Bounded and Loaded from Use Condition

摘要

This paper considers type I censored ramp tests for Weibull lifetime distribution when there are limitations on test stress which loaded from use condition. The inverse power law and a cumulative exposure model are assumed. Maximum likelihood (ML) estimators of model parameters and their asymptotic covariance matrix are obtained. The optimum ramp test plans are also found which minimize the asymptotic variance of the ML estimator of a specified quantile of log lifetime at design constant stress.