TY - JOUR
T1 - On the Transferability of Fatigue and Cyclic Deformation Data to 100 µm Thin Structures
AU - Himmelbauer, Florian
AU - Winter, Gerhard
AU - Grün, Florian
AU - Kiesling, Constantin
N1 - Publisher Copyright:
© 2022 by the authors.
PY - 2022/9/15
Y1 - 2022/9/15
N2 - The fatigue properties and cyclic deformation behaviour of materials are usually determined using cylindrical specimens (e.g., Ø7.5 mm). Since the transferability to very small dimensions has not been comprehensively considered so far, this study investigates the transferability of specimen data from high-strength steel X5CrNiCuNb16-4 to real structures characterised by a wall thickness of 100 µm. Regarding fatigue, extensive calculations demonstrate that for notched specimens and thin structures, both the material-mechanical support factor concept according to the FKM guideline and the point method of the Theory of Critical Distance (TCD) make correct predictions of the local fatigue strength, with a maximum deviation from experimental values of less than 5%. However, the study points out that the TCD is only conditionally applicable for thin-walled structures, as the material parameter (Formula presented.) must be significantly smaller than the wall thickness. Regarding the deformation behaviour, the material reveals special flow characteristics in the first hysteresis. Nevertheless, a combined hardening approach is suitable for modelling. The validation of the model by a plastic deformation of the structure seems plausible, although geometric influences prove to be dominant. In conclusion, even 100 µm thin structures can be evaluated using conventional specimen tests and established assessment or modelling methods.
AB - The fatigue properties and cyclic deformation behaviour of materials are usually determined using cylindrical specimens (e.g., Ø7.5 mm). Since the transferability to very small dimensions has not been comprehensively considered so far, this study investigates the transferability of specimen data from high-strength steel X5CrNiCuNb16-4 to real structures characterised by a wall thickness of 100 µm. Regarding fatigue, extensive calculations demonstrate that for notched specimens and thin structures, both the material-mechanical support factor concept according to the FKM guideline and the point method of the Theory of Critical Distance (TCD) make correct predictions of the local fatigue strength, with a maximum deviation from experimental values of less than 5%. However, the study points out that the TCD is only conditionally applicable for thin-walled structures, as the material parameter (Formula presented.) must be significantly smaller than the wall thickness. Regarding the deformation behaviour, the material reveals special flow characteristics in the first hysteresis. Nevertheless, a combined hardening approach is suitable for modelling. The validation of the model by a plastic deformation of the structure seems plausible, although geometric influences prove to be dominant. In conclusion, even 100 µm thin structures can be evaluated using conventional specimen tests and established assessment or modelling methods.
KW - combined hardening model
KW - fatigue strength assessment
KW - material modelling
KW - support factor
KW - theory of critical distance
KW - thin-walled structures
KW - transferability
UR - http://www.scopus.com/inward/record.url?scp=85138671616&partnerID=8YFLogxK
U2 - 10.3390/met12091524
DO - 10.3390/met12091524
M3 - Article
AN - SCOPUS:85138671616
SN - 2075-4701
VL - 12
JO - Metals
JF - Metals
IS - 9
M1 - 1524
ER -