Integrating degradation model with stress strength interference model to estimate reliability in design phase

While working on New Product Developments (NPD), it is a common practice to make use of stress strength interference model to estimate the reliability of a product during the early design stage. However, it is very important to take into account the possible degradation in the strength of the material as it is put into operation. This paper is an attempt to make use of test data available for a specific product that was sourced from two different suppliers. Degradation model was built on the small scale replicate (called as coupon) for which the test data was available. This helped to understand the level of degradation over the time period which was then superimposed on the Stress Strength interference model to evaluate the reliability over time. Further, such estimation provides designers forehand information on potential to achieve the allocated component level reliability target derived from system level reliability allocation.