Improved description of low-cycle fatigue behaviour of 316L steel under axial, torsional and combined loading using plastic J-integral

0557313 - ÚFM 2023 RIV NL eng J - Journal Article
Slávik, Ondrej - Vojtek, Tomáš - Poczklán, Ladislav - Tinoco Navaro, Hector Andres - Kruml, Tomáš - Hutař, Pavel - Šmíd, Miroslav
Improved description of low-cycle fatigue behaviour of 316L steel under axial, torsional and combined loading using plastic J-integral.
Theoretical and Applied Fracture Mechanics. Roč. 118, APR (2022), č. článku 103212. ISSN 0167-8442. E-ISSN 1872-7638
R&D Projects: GA ČR(CZ) GJ19-25591Y; GA ČR(CZ) GA18-03615S
Institutional support: RVO:68081723
Keywords : crack-growth * propagation * strain * threshold * damage * Plastic Jintegral * Multiaxial loading * Low-cycle fatigue * Equivalent plastic strain * Austenitic stainless steel
OECD category: Materials engineering
Impact factor: 5.3, year: 2022
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0167844221003086?via%3Dihub

Low-cycle fatigue behaviour and fatigue crack kinetics of the 316L austenitic stainless steel were studied under cyclic axial, torsional and in-phase combined loading using hollow cylindrical (tubular) specimens with a small hole for crack initiation. The concept of plastic. J-integral was used, which was shown in previous studies to unify the crack growth rate data for several different materials. Dependencies of Jp on crack length were determined by extensive finite element modelling considering non-linear material behaviour according to the cyclic stress-strain curve. Locally deflected cracks were modelled in accordance with amplitudes of the axial and torsional components of combined loading. The measured crack growth rate diagrams for all types of loading and for various loading amplitudes were unified using amplitude of Jp. Fatigue lives under torsional loading were much longer than under axial loading for the same equivalent plastic strain amplitude, which was explained by higher crack driving forces in terms of Jp under axial loading than under torsional loading. Fatigue lives estimated by crack propagation based on a master curve in terms of Jp,a were in a good agreement with those obtained experimentally under all types of loading. The used concept can reduce the experimental program to obtaining of material data only for axial loading, which can then be used for prediction of behaviour under in-phase multiaxial loading. The von Mises formula for multiaxial low-cycle fatigue loading eeq,p2 = ep2 + 7p2 / 3 was modified so that the fatigue lives under axial, torsional and combined loading were characterized in a matching way. Using the formula ep,Nf2 = ep2 + 7p2 / 25, the fatigue life data fell on a single Coffin-Manson curve.
Permanent Link: http://hdl.handle.net/11104/0331351