In engineering practice, the design of a component is normally ascertained based on deterministic material data and component loading scenarios. The considered loads are based on experiences, measured data and load scenarios covering a whole variety of possible service load cases. Minimum values from standards or measurements are generally used as material properties. Such a procedure delivers information concerning whether a component can be operated in service, also incorporating an additional safety margin. However, it is not taken into account that, in reality, deviations from the assumed input data may occur with a certain probability. Such deviations may be caused by e.g. scatter of material properties, disordered microstructures, defects in materials, deviations from the given construction, manufacturing defects, unknown internal stresses such as residual welding stresses or unexpected external loads. The aim of a probabilistic component assessment is to account for the probable occurrence of such deviations in the component integrity assessment as well as to predict the component behavior and its reliability. Often, such reliability checks are essential both for the risk analysis and to avoid violations of warranty statements.
The research and development work at Fraunhofer IWM focuses on the probabilistic material and component assessment of modern materials such as fiber-reinforced materials, polymeric or metallic foams, high-strength steels, casted irons or steel alloys as well as weldments. In these materials, which are applied in various industrial sectors – from the automotive and aviation sector to medical components – differences in their microstructure or existing micro or macro defects have a significant influence on strength features. By means of probabilistic analyses, heterogeneous microstructures and the related property scatter can be considered to achieve a comprehensive safety and reliability assessment.