Description of short fatigue crack propagation under low cycle fatigue regime

0465128 - ÚFM 2017 RIV NL eng C - Conference Paper (international conference)
Hutař, Pavel - Poduška, Jan - Chlupová, Alice - Šmíd, Miroslav - Kruml, Tomáš - Náhlík, Luboš
Description of short fatigue crack propagation under low cycle fatigue regime.
21st European Conference on Fracture. Amsterdam: Elsevier, 2016, s. 3010-3017. Procedia Structural Integrity, 2. ISSN 2452-3216.
[ECF21 - European Conference on Fracture /21./. Catania (IT), 20.06.2016-24.06.2016]
R&D Projects: GA ČR GA15-08826S; GA MŠMT LM2015069
Institutional support: RVO:68081723
Keywords : short fatigue cracks * low cycle fatigue * plastic part of J-integral * numerical modelling
OECD category: Audio engineering, reliability analysis

Measurement of the short fatigue crack propagation can come across a lot of difficulties from the experimental point of view and interpretation of the results is also sometimes controversial. For simplicity, usual description of the short cracks is based on linear elastic fracture mechanics (using the concept of stress intensity factor). In this case, significant differences between short cracks and long cracks are usually presented. Most of the discrepancies are simply given by non-validity of the linear elastic fracture mechanics approach. In our case of physically short fatigue cracks the level of applied stress is close to cyclic yield stress of the material and, due to large amount of plasticity, conditions of linear elastic fracture mechanics are not satisfied. As a consequence, non-linear elastic plastic fracture mechanics is used for description of the short crack behavior in this article. Concept based on plastic part of J-integral is proposed for the description of the short crack behavior and data obtained for different strain amplitudes are compared. This concept is validated on experimental data obtained on steel 316L.
Permanent Link: http://hdl.handle.net/11104/0264218