At the beginning, preliminary studies regarding the simulation of unnotched and notched structures considering the period of crack initiation and fatigue crack propagation were performed. The effect of heat treatment on lifetime was studied by simulations of crack growth in solid components. In this case, the software tool NASGRO was used for lifetime calculations. The results of the components’ lifetime simulations show the absolute necessity of heat treatment. Depending on the maximum value of cyclic loading, the residual lifetime can be increased by the factor 34 and 17 respectively. In order to perform the simulation of notched parts including crack initiation and fatigue crack propagation, -the software tool Franc/FAM was employed.
In the first step of experimental research, preliminary tests on modified CT-specimens containing one hole will be performed, Figure 2. In this step, different parameter like hole size or hole position will be examined. Furthermore, the number of holes will be elevated to a row of holes, positioned inside the specimen. In the next step, samples with different notch positions will be produced in order to investigate life time manipulation due to crack deflection. After that, elongated holes with different orientations will be tested in order to investigate life time manipulation due to different crack deflection situations. In the last step, the number of rows will be heightened to an array of holes. The findings of this test series will be used to describe the crack growth performance in high-grade notched structures.