High frequency resonance pulsator

• Subject Area: Materials Engineering
• Term: Funded in 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 468976436

The fatigue life of materials and components is limited when they are subjected to repeated mechanical loads, which is why an understanding of the damage development, taking into account influencing factors, and the estimation of the fatigue life based on this are of great importance for technical applications. In this context, it is important to differentiate between the fatigue life ranges in which materials and components are subjected to fatigue loads, since the damage mechanisms change from the low-cycle-fatigue (LCF) to the high-cycle-fatigue (HCF) and to the very-high-cycle-fatigue (VHCF) range.In the sense of a (remaining) fatigue life estimation or evaluation, it is therefore necessary that comprehensive material information is determined and provided, which describes the microstructure and the associated material mechanisms. Measurement techniques based on thermometry, resistometry and magnetics are able to detect microstructural changes of metallic materials in early fatigue stages and thus provide a significant gain in information compared to conventional stress-strain hysteresis measurements. The measured values and curves provided in fatigue tests using the aforementioned methods can be used as input variables in the short-time methods for fatigue life calculations StressLife, StrainLife and SteBLife developed by the applicant, which can significantly reduce the test and cost effort required to provide fatigue data. It should be noted here that the applicant's investigations to date have been limited to the LCF and HCF range due to the existing test infrastructure, which repeatedly leads to restrictions with regard to the application potential of the short-time methods. The aim of the application for large-scale equipment is therefore the procurement of a high-frequency test system, which should provide the possibility of extending the test spectrum to the VHCF range, which should also enable the extension of the short-time methods StressLife, StrainLife and SteBLife using the above-mentioned measurement procedures and methods. This results in new questions that are within the research strategy of the Department of Materials Science and Testing at the University of Applied Sciences of Kaiserslautern. The applicant is well aware that the damage mechanisms in the HCF and VHCF areas are different and must be considered in a differentiated manner, however, experience from completed research projects can be drawn upon. In addition, the proposed test system should provide the possibility of reducing the test time for validation tests due to the higher test frequencies (statistical validation) and also enable investigations into the dependence of the deformation rate, which should also be included as a parameter extension in the above-mentioned short-time methods.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Hochfrequenz-Resonanzpulsator
• Instrumentation Group: 2910 Dynamische Prüfmaschinen und -anlagen, Pulser
• Applicant Institution: Hochschule Kaiserslautern
• Leader: Professor Dr.-Ing. Peter Starke