New Method for Determining Reliability Demonstration Test Plan with Exponential Subsystem Data

Existing Bayesian reliability demonstration method only make use of system level data to form the prior distribution. This becomes a problem when the only prior data available are the subsystem test data. Such scenario does happen for large scale electronic equipment. To solve this problem, a method is proposed to derive the Bayesian reliability demonstration test plan for systems with exponential subsystem data. Firstly, the subsystem test data are used to calculate the confidence bound of system failure rate. Then, the two percentile method is applied to determine the prior distribution of system failure rate. Finally, a new reliability demonstration test plan is defined according to the Bayesian maximum posterior risk rule. The suggested method can reduce the test duration significantly and is most beneficial for systems that have subsystem test data before the reliability demonstration. A numerical example at the end of the paper illustrates the method.