Charakterisierung und Simulation der VHCF-Schädigungsentwicklung auf Basis des Resonanzverhaltens am Beispiel eines metastabilen Austenitstahls

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The characterization and simulation of the VHCF behavior of a stable and a metastable austenitic stainless steel based on the resonance behavior will be extended in the second phase of this project by including locally occurring damage mechanisms and taking the effect of temperature into account. The influence of temperature increase resulting from the high frequency technology applied occur in combination with microstructural changes (dislocation density and arrangement, phase transformation processes, surface roughening, crack initiation) and hence leads to an effect on the resonance behavior, which is not quantitatively known yet. In order to ensure the practical relevance of the results obtained so far and in the remaining time of the first phase of the project, a clear separation of the influencing factors is important. For this purpose, the influence of temperature should be investigated using novel experimental techniques (e.g. damping measurements during isothermal fatigue tests at elevated temperatures) and the temperature should be included as a parameter in the simulation model. The three-dimensional investigations of real microstructures and their incorporation into the simulation provide information of the local distribution of the damage processes studied and complete the description of the transient behavior. The characterization of locally occurring damage mechanisms (strain localization, crack initiation, crack growth) will be added to the previous investigated global damage behavior. The effect of these mechanisms on the resonant behavior will be systematically studied and accounted for in the simulation. The development of testing methodology and new monitoring techniques (e.g., the investigation of the nonlinear material behavior) will concomitantly to the above-mentioned studies be carried out and thus represents another important issue of the research project.