Issue 47

S. Bressan et alii, Frattura ed Integrità Strutturale, 47 (2019) 126-140; DOI: 10.3221/IGF-ESIS.47.10

Influence of notch sensitivity and crack initiation site on low cycle fatigue life of notched components under multiaxial non-proportional loading

Stefano Bressan Graduate School of Science and Engineering, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu-shi, Shiga, 525-8577, Japan gr0300kf@ed.ritsumei.ac.jp Fumio Ogawa, Takamoto Itoh Department of Mechanical Engineering, College of Science and Engineering, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu shi, Shiga, 525-8577, Japan itohtaka@fc.ritsumei.ac.jpyahoo.com, ogawa-f@fc.ritsumei.ac.jpyahoo.com Filippo Berto Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Richard Birkelands vei 2b, 7491, Trondheim, Norway filippo.berto@ntnu.no

A BSTRACT . A series of strain controlled multiaxial low cycle fatigue (LCF) tests under proportional and non-proportional loading conditions have been conducted on notched specimens. Cylindrical bars of Al 6061 aluminum alloy and AISI 316L stainless steel with four values of stress concentration factors referred to the net section K t,n were employed. The experimental results evidenced a reduction of fatigue life due to non-proportional loading. Furthermore, the crack initiation site has been detected to be moved from the notch tip in the case of steel for high values of notch radius under non proportional loading. Stress concentration factor evaluated in the elastic field K t,n has been included in the Itoh-Sakane parameter to evaluate the fatigue life, returning a general underestimation of fatigue life especially for high values of K t,n . Material notch sensitivity and crack initiation position have been taken into account to further modify the model, improving the original results and showing a better assessment. K EYWORDS . Non-proportional loading; Notch; Multiaxial loading; Low cycle fatigue; Crack initiation.

Citation: Bressan, S., Ogawa, F., Takamoto, I., Berto, F., Influence of notch sensitivity and crack initiation site on low cycle fatigue life of notched components under multiaxial non proportional loading, Frattura ed Integrità Strutturale, xx (2019) ww-zz.

Received: 11.11.2018 Accepted: 24.11.2018 Published: 01.01.2019

Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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