Some recent results on the fatigue strength of notched specimens made of 40CrMoV13.9 steel at room and high temperature

Abstract

The work summarizes a large bulk of experimental data from specimens made of 40CrMoV13.9 steel. The first part of the paper deals with multiaxial fatigue strength of notched round bars tested under combined tension and torsion loading, both in-phase and out-of-phase. The results from multi-axial tests are discussed together with those obtained under pure tension and pure torsion loading from notched specimens with the same geometry. The second part of the paper summarizes data from uniaxial-tension stress-controlled fatigue tests on specimens made of the same steel. Tests are performed varying temperature, from room temperature up to 650°C. Altogether more than 180 new fatigue data are summarised in the present work, corresponding to more than two-years of testing programme. All fatigue data are presented first in terms of nominal stress amplitudes referred to the net area and then re-analysed in terms of the mean value of the strain energy density evaluated over a given, crescent shape volume embracing the stress concentration region. For the specific steel, the radius of the control volume is found to be independent of the loading mode

A review of multiaxial fatigue criteria for random variable amplitude loads

“…Multiaxial fatigue has been a wealthy research topic for the past few decades, as is demonstrated by the text book of Socie and Marquis and that of Susmel fully devoted to this topic, and by the numerous publications of many research groups (for example, Lazzarin‐Berto, Ellyin‐Kujawski, McDowell, Zenner and the present authors). Some recent publications pertaining to specific aspects concerning fatigue and fracture under complex multiaxial loading can also be mentioned …”

Study on the Microstructure and Properties of Welded Joints of Laser Shock Peening on HC420LA Low-Alloy High-Tensile Steel

“…Figure 9c shows the fiber zone of the impact fracture of the untreated specimen with a large number of toughness fractures characterized by tearing ridges with microporosity of the toughness nests and a small number of swirls and slip surfaces. Combined with other scholars' studies [24,25] that explain this phenomenon and according to the translational-rotational-vortex theory, the local occurrence of plastic deformation when the specimen is subjected to impact loading will accumulate a large number of defects in the subsurface and around the notch, thus forming a macroscopic crack due to the vortex effect of plastic flow. This forms a rotational-shear deformation zone owing to the rapid development of the local fracture.…”

A review of the fatigue strength of structural materials under multiaxial loading in terms of the local energy density

“…It is worth mentioning that some recent interesting applications have been considered by using the SED approach including multiscale approaches and high temperature (He et al, 2015;Berto et al, 2014;Berto et al, 2015bBerto et al, , 2015cGallo et al, 2016aGallo et al, , 2016b). The SED is also able to automatically take into account three-dimensional effects and induced modes generally occurring in real structures (Berto et al, 2004;Berto et al, 2011b;2011c, 2011d, 2012a, 2013aHarding et al, 2010;Pook et al 2015aPook et al , 2016Pook et al , 2017He et al, 2016aHe et al, , 2016bHe et al, , 2016cKotousov et al, 2012Kotousov et al, , 2013Afshar et al 2013) Different materials and loading conditions have been considered showing the sound applicability of the method to many loading configurations and the connections to other local approached based on the notch stress intensity factors (Torabi et al, 2015(Torabi et al, , 2016a(Torabi et al, , 2016bMirsayar et al, 2016;Aliha et al, 2015Aliha et al, , 2016aAliha et al, , 2016bAliha et al, , 2017aRazavi et al, 2017Berto, 2013Berto, , 2015aBerto, , 2015bBerto et al, 2014, 2015b, Ayatollahi et al, 2015Ferro et al, 2012…”