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Machining of reproducible flaws corresponding to fatigue cracks for fracture mechanics tests of components and welded joints
Author(s) -
Wobst Klaus,
Baumbach Ute,
Krafka Helmut,
Aurich Dietmar
Publication year - 1993
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199301055
Subject(s) - fatigue testing , structural engineering , welding , fracture mechanics , materials science , joint (building) , fracture (geology) , composite material , engineering
In connection with the analysis and the development of failure concepts in fracture mechanics for quasistatic loaded components and elastic‐plastic behaviour of the material, tests are also carried out with welded and/or complex shaped specimens or structures. Thereby the difficulty arises of generating reproducible flaws in the form of fatigue precracks in definite positions in the components, respectively in the welded joint. It is reported exemplarily about experiments on different CT25 and CCT specimens and on a pressure vessel which contained a fatigue pre‐crack, a 0.2 mm saw cut or notches with notch root radius ≤ ≥ 0.1 mm as flaws. The comparison of the results with regard to J ‐integral at initiation of stable crack, J i , and J R curves shows that under certain conditions the 0.2 mm saw cut (notch root radius ≤ ≤ 0.02 mm) is a useful alternative, if reproducible generation of a fatigue pre‐crack will not be successful or too expensive. The tests were carried out on StE 460 and on a welded joint of this steel at 25 ± 2°C.