Entwicklung eines Lebensdauervorhersagekonzepts im VHCF-Bereich auf der Basis kovariater mikrostruktureller Merkmalsgrößen

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The aim of the desired project is the study of statistical models and methods for a fatigue lifeprediction concept with the utmost possible accuracy as well as its experimental validation in theVHCF range. Already available and additional fatigue results and microstructural analysesregarding the VHCF behavior for two structural materials, the Ni-base superalloy Nimonic 80A undthe austenitic steel 1.4301, serve as database. The proposed mathematical research work cangenerally be attributed to the field of extreme value theory under consideration of covariateinformation. The covariate information relates to failure-governing microstructural features (e.g.maximum inclusion size, misorientation of neighboring grains, surface roughness etc.). Using theextreme value theory the conditional distribution of a specimen fatigue life depending on theapplied stress amplitude as well as complex covariates should be simulated and fitted to the dataobtained. Hence, a basis for the development of well-grounded evidences for appropriate riskparameters such as stress and number of cycles to failure as basis for the well-known SN-curve iscreated. The close link between the statistical simulation and experimental investigations is acentral part of the project. The experimental results for two structural materials in the VHCF rangeshould immediately enter into the statistical modeling, and the obtained findings should be used forthe design of experiments.