This presentation starts with an introduction of a DFR process. Then the challenges of reliability demonstration test (RDT) in the Validation phase will be illustrated by applying a classical RDT (CRDT) approach, which may require a large sample size to demonstrate the required high reliability at acceptable confidence levels. This is true in demonstration of the required reliability at subsystem or component level, after product reliability requirement allocation activity in the DFR process.
Bayesian reliability demonstration test (BRDT) approach can be adopted to significantly reduce sample size or testing duration. In the present work, we will enhance BRDT in several aspects:
We will show how BRDT can be an integrated part of the whole DFR process, by linking to FMEA, PoF, and reliability requirement flow down or allocation.
Successful application of a Bayesian approach depends on the prior experience or life data (testing or field) from previous generations of the product under design. However, there is a case when the product or design is totally new and there is no prior product life data from testing or field. It can be shown in our present work that BRDT can still be used successfully for a totally new product design and development, with the DFR process.
Bayesian reliability approaches involve challenging mathematical operations for engineers, like integrations needing numerical methods. We simplify the BRDT approach based on the prior distribution characteristics of reliability in a DFR process. The approach given in the present paper can be used very easily by engineers with any standard spreadsheet application calculation.