Reliability Life Estimation of Products Using Accelerated life-testing

Abstract

In order to identify design weaknesses and improve reliability for a product as soon as possible, accelerated life-testing is extensively used. Accelerated life-testing (ALT) is either to accelerate the number of cycle per unit time (frequency acceleration) or to increase the stress-levels when operating (stress acceleration). In this paper, Constant-stress accelerated life-testing is used construct the accelerated function. Singly right censoring is considered to form the failure distributions at various stress levels. The characteristic parameters (location and scale) for each distribution are estimated by incorporating the methods of best linear unbiased estimators with the theory of order statistics. The scale parameter being minimum variance is derived out using the technique of Lagrange Multiplier. A log-linear life-stress relationship is suggested to formulate the accelerated equation. The unknown coefficients the accelerated equation are obtained using Gauss-Markov theorem. Once the scale parameter and the unknown coefficients determined, the life normal operating condition and the related reliability measures could then be evaluated. Typically, several cases involving various failure distributions are used as examples to depict the estimated procedures ALT.