Issue 41

S.M.J. Razavi et alii, Frattura ed Integrità Strutturale, 41 (2017) 440-446; DOI: 10.3221/IGF-ESIS.41.55 440 40CrMoV13.9 notched specimens under multiaxial fatigue: an overview of recent results S.M.J. Razavi, M. Peron, J. Torgersen, F. Berto, T. Welo Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Norway javad.razavi@ntnu.no , mirco.peron@ntnu.no , jan.torgersen@ntnu.no , filippo.berto@ntnu.no A BSTRACT . The multiaxial fatigue strength of circumferentially V-notched and semicircular notched specimens made of 40CrMoV13.9 has been investigated in this paper. The multiaxial load were applied using combined tension and torsion loading, both in-phase and out-of-phase. The axis- symmetric V-notched specimens were characterized by a blunt notch tip (radius: 1 mm) and notch opening angle of 90 o and the semicircular specimens were characterized by a constant notch tip radius. The net sectional area of both cases was equal with a diameter of 12 mm. The notched specimens were tested under pure mode I (tension), mixed mode I/III and pure mode III (torsion). More than 120 fatigue test data are used in this paper to evaluate the fatigue behaviour of 40CrMoV13.9 alloy. All fatigue data are analysed using the Average Strain Energy Density (ASED) criterion which employs the mean value of the strain energy density evaluated over a finite size semicircular sector surrounding the tip of the notch to predict the fatigue life of the tested specimens. K EYWORDS . Multiaxial fatigue; SED criterion; Notched components; Mixed mode I/III. Citation: Razavi, S.M.J., Peron, M., Torgersen, J., Berto, F., Welo, T., 40CrMoV13.9 notched specimens under multiaxial fatigue: an overview of recent results, Frattura ed Integrità Strutturale, 41 (2017) 440-446. Received: 18.05.2017 Accepted: 27.05.2017 Published: 01.07.2017 Copyright: © 2017 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. I NTRODUCTION he majority of engineering components are subjected to complex multiaxial loading histories. This makes it especially important to be able to accurately estimate fatigue damage under multiaxial loading. To this end, considerable effort in the past decades has been put into developing damage parameters which reflect the actual damage mechanisms of the multiaxial fatigue failure process [1-6]. Numerous predictive methods have been proposed in the literature for the cracked and notched components under multiaxial loading including the critical plane [7,8], energetic criterion [9] and thermodynamics based method [10]. Nieslony and Sonsino [11] conducted a comparison among different available failure criteria considering a large bulk of experimental data from notched specimens. Ayatollahi et al. [12] proposed a local numerical method in order to predict the fatigue crack initiation and propagation in the cracked and T