In the automotive industry, the reliability of products is often defined by a so-called B10-value. That means, that at a defined point in time, the maximal failure probability is 10 %. Due to the fact that the B10-value correlates to the required service, it is quite challenging to proof a service life expectation, for example 250.000 km for a passenger car, in a quite short time frame for testing activities within a product development project. During the development of products, the proof of product reliability is therefore a challenging activity.
In addition to a procedural flow of test planning, correlations between reliability requirements and various test parameters such as test duration and sample size are shown. The test quality is evaluated by the confidence level, whose dependencies are also determined.
Especially uncertainties and their consequences are part of this study. One example is the estimation of the shape parameter of a Weibull distributed failure characteristic in the planning phase. Possible sources for the estimation and the consequences of uncertainties of the estimation are analyzed.
After performing a reliability demonstration test, the impact of uncertainties on the results are under consideration. The effects of uncertainties of the planning phase, e.g. uncertainties of the estimation of the Weibull shape parameter, to the demonstrated reliability and the confidence level are shown. Finally, case studies give an impression of the importance of the uncertainties.