Quantified evaluation of the frequency influence on the fatigue behavior of unalloyed steels for implementing in resource-efficient fatigue life prediction methods

For a reliable service life prediction, it is necessary to determine comprehensive material information that takes into account the microstructure and the associated material mechanisms. In this context, non-destructive testing (NDT) methods, such as temperature-based, resistometric and magnetics-based measurement methods, are particularly suitable for detecting microstructural changes at early fatigue stages and thus providing a considerable gain in information compared with conventional measurement methods. This has been confirmed in previous research projects, which focused in particular on the transition between LCF (low cycle fatigue) and HCF (high cycle fatigue) as well as the HCF area. Systematic investigations will now be carried out to analyze the extent to which this can be transferred to lower stress levels and higher cycle numbers. A change in the damage mechanisms from the HCF to the VHCF (Very High Cycle Fatigue) range must be taken into account. The measurement curves detected in fatigue tests based on the ZFP can be used as input variables for the StressLife and StrainLife life prediction methods (LPV).

Comprehensive mechanical tests to extend the LPV at WWHK are supplemented by a detailed characterization of the microstructure by means of different scanning electron microscopic investigations at WPT. The steel C45E in the normalized state serves as the test material, which already provides a database for the test frequency of 5 Hz as a reference in completed investigations. Thus, a frequency range of 80 to 260 Hz is used in the research project using a resonance test system.

HSKL

Studiengangsleitung: "Automatisierungstechnik, Bachelor" "Elektrotechnik - berufsbegleitend, Bachelor" "Industrial Engineering, Bachelor" "Maschinenbau, Bachelor" "Maschinenbau - berufsbegleitend, Bachelor" "Mechatronik, Bachelor" "Mechatronik - berufsbegleitend, Bachelor" "Prozessingenieurwesen, Bachelor" "Wirtschaftsingenieurwesen, Bachelor" " Wirtschaftsingenieurwesen - berufsbegleitend, Bachelor", Fachbereichsrat AING

HSKL

Wissenschaftlicher Mitarbeiter

The aim is to expand the established LPV for the HCF regime for a frequency of 5 Hz for higher frequencies (up to 260 Hz) and higher cycle numbers (up to 108) and thus to describe the transition between LCF/HCF and VHCF regime and to validate using conventional constant amplitude tests (CAT). In this connection a multi-parameter approach is being developed, which takes the frequency and deformation rate influences into account.