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

基于共振行为的稳定和亚稳奥氏体不锈钢的VHCF行为的表征和模拟将在该项目的第二阶段中扩展，包括局部发生的损伤机制并考虑温度的影响。由所应用的高频技术引起的温度升高的影响与微观结构变化（位错密度和排列、相变过程、表面粗糙化、裂纹萌生）结合发生，因此导致对共振行为的影响，这尚未定量地知道。为了确保迄今为止所取得的成果和项目第一阶段剩余时间内的实际相关性，必须明确区分影响因素。为此，应使用新的实验技术（例如，在高温下进行等温疲劳试验期间的阻尼测量）研究温度的影响，并应将温度作为参数纳入模拟模型。三维调查的真实的微观结构，并将其纳入模拟提供的信息的局部分布的损伤过程的研究和完成的瞬态行为的描述。局部发生的损伤机制（应变局部化，裂纹萌生，裂纹扩展）的表征将被添加到先前研究的全局损伤行为。这些机制对谐振行为的影响将在模拟中系统地研究和解释。开发测试方法和新的监测技术（例如，非线性材料行为的研究）将与上述研究同时进行，因此代表了研究项目的另一个重要问题。

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.