The next step is to derive reference loads which are used within the development process and fundamental for release tests. Measured data is analysed and extrapolated to a given design life based on the classification of factor models (which type of load cases are relevant) and the application of usage models (how often do these load cases occur in a certain customer group). High quantiles of the corresponding distributions are used to define the reference loads.
That process was, among others, executed in a common project with Volkswagen Nutzfahrzeuge and reported during the VDI conference Commercial Vehicles 2015 in Eindhoven. Some of the applied methods, e.g. extending the evaluation of measured data using geo-referenced information and the statistical analysis based on factor models, were presented in more detail during the DVM-conference of the AK Betriebsfestigkeit 2016 in Steyr.
For demonstrating the required reliability of a component based on release tests, safety factors are introduced to cope with the remaining uncertainty due to lack of knowledge in the extreme tails of the load and strength distributions. In addition, statistical reasoning is needed for estimating how many specimens have to be tested in order to prove a certain reliability with a certain confidence.
The department MDF develops and applies methods for supporting the sketched process with focus on the vehicle industry including construction and agricultural machinery. However, other applications such as wind turbines or railway industry are also covered. Most of the methods are applicable within the assessment of energy efficiency or fuel consumption as well.