Design of Reliability Tests Based on Simple-Step-Stress Model

Abstract

Accelerated life tests are frequency used to obtain information on life distribution of products quickly. The products can be submitted to higher level of stress in various ways such as constant, step, and progress stress. In a constant-stress test, products are run at some constant level of stress until all products fail or a time limit is reached. A step-stress test allows the stress setting to be changed at a prescribed time or upon the occurrence of a fixed number of failures. In a progress-stress test, the stress is continuously increased over time. Under the assumption of the functional relationship between the parameters of failure distribution and applied stress, there are many studies about parameter estimation using data obtained from an accelerated life test. In this paper, instead of the parameter estimate problem, we consider a new design procedure of simple-step-stress accelerated life tests for assuring the mean time to failure at usual stress with specified producer and consumer risks under the condition that the parameters of the failure distributions at two stress levels are provided. The practical use of the proposed design procedure is illustrated through some numerical examples.