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Keisuke Tanaka - One of the best experts on this subject based on the ideXlab platform.

  • averaged strain energy density based synthesis of Crack initiation Life in notched steel bars under torsional fatigue
    Fracture and Structural Integrity, 2016
    Co-Authors: Filippo Berto, Alberto Campagnolo, Giovanni Meneghetti, Keisuke Tanaka
    Abstract:

    The torsional fatigue behaviour of circumferentially notched specimens made of austenitic stainless steel, SUS316L, and carbon steel, SGV410, characterized by different notch root radii has been recently investigated by Tanaka. In that contribution, it was observed that the total fatigue Life of the austenitic stainless steel increases with increasing stress concentration factor for a given applied nominal shear stress amplitude. By using the electrical potential drop method, Tanaka observed that the Crack nucleation Life was reduced with increasing stress concentration, on the other hand the Crack Propagation Life increased. The experimental fatigue results, originally expressed in terms of nominal shear stress amplitude, have been reanalysed by means of the local strain energy density (SED) averaged over a control volume having radius R0 surrounding the notch tip. To exclude all extrinsic effects acting during the fatigue Crack Propagation phase, such as sliding contact and/or friction between fracture surfaces, Crack initiation Life has been considered in the present work. In the original paper, initiation Life was defined in correspondence of a 0.1÷0.4-mm-deep Crack. The control radius R0 for fatigue strength assessment of notched components, thought of as a material property, has been estimated by imposing the constancy of the averaged SED for both smooth and Cracked specimens at NA = 2 million loading cycles. KEYWORDS. Torsional fatigue; Notch effect; Crack initiation; Averaged SED; Electrical potential drop

  • synthesis of Crack initiation Life in steel notched specimens under torsional fatigue based on the averaged strain energy density
    Procedia structural integrity, 2016
    Co-Authors: Alberto Campagnolo, Giovanni Meneghetti, Filippo Berto, Keisuke Tanaka
    Abstract:

    Abstract The torsional fatigue behaviour of circumferentially notched specimens made of austenitic stainless steel, SUS316L, and carbon steel, SGV410, characterized by different notch root radii has been recently investigated by Tanaka. In that contribution, it was observed that the total fatigue Life of the austenitic stainless steel increases with increasing stress concentration factor for a given applied nominal shear stress amplitude. By using the electrical potential drop method, Tanaka observed that the Crack nucleation Life was reduced with increasing stress concentration, on the other hand the Crack Propagation Life increased. The experimental fatigue results, originally expressed in terms of nominal shear stress amplitude, have been reanalysed by means of the local strain energy density (SED) averaged over a control volume having radius R 0 surrounding the notch tip. To exclude all extrinsic effects acting during the fatigue Crack Propagation phase, such as sliding contact and/or friction between fracture surfaces, Crack initiation Life has been considered in the present work (*). In the original paper, initiation Life was defined in correspondence of a 0.1÷0.4-mm-deep Crack. The control radius R 0 for fatigue strength assessment of notched components, thought of as a material property, has been estimated by imposing the constancy of the averaged SED for both smooth and Cracked specimens at N A = 2 million loading cycles. (*) A version of the present contribution has already been presented at the 11 th International Conference on Multiaxial Fatigue and Fracture (ICMFF11).

  • Averaged strain energy density-based synthesis of Crack initiation Life in notched steel bars under torsional fatigue
    Gruppo Italiano Frattura, 2016
    Co-Authors: Filippo Berto, Alberto Campagnolo, Giovanni Meneghetti, Keisuke Tanaka
    Abstract:

    The torsional fatigue behaviour of circumferentially notched specimens made of austenitic stainless steel, SUS316L, and carbon steel, SGV410, characterized by different notch root radii has been recently investigated by Tanaka. In that contribution, it was observed that the total fatigue Life of the austenitic stainless steel increases with increasing stress concentration factor for a given applied nominal shear stress amplitude. By using the electrical potential drop method, Tanaka observed that the Crack nucleation Life was reduced with increasing stress concentration, on the other hand the Crack Propagation Life increased. The experimental fatigue results, originally expressed in terms of nominal shear stress amplitude, have been reanalysed by means of the local strain energy density (SED) averaged over a control volume having radius R0 surrounding the notch tip. To exclude all extrinsic effects acting during the fatigue Crack Propagation phase, such as sliding contact and/or friction between fracture surfaces, Crack initiation Life has been considered in the present work. In the original paper, initiation Life was defined in correspondence of a 0.1÷0.4-mm-deep Crack. The control radius R0 for fatigue strength assessment of notched components, thought of as a material property, has been estimated by imposing the constancy of the averaged SED for both smooth and Cracked specimens at NA = 2 million loading cycle

  • fatigue behavior of circumferentially notched round bars of austenitic stainless steel under torsional and axial loads
    ASME 2010 Pressure Vessels and Piping Division K-PVP Conference, 2010
    Co-Authors: Masao Itatani, Keisuke Tanaka, Isao Ohkawa, Takehisa Yamada, Toshiyuki Saito
    Abstract:

    Fatigue tests of smooth and notched round bars of austenitic stainless steels SUS316NG and SUS316L were conducted under cyclic tension and cyclic torsion with and without static tension. Fatigue strength under fully reversed (R=−1) cyclic tension once increased with increasing stress concentration factor up to Kt =1.5, but it decreased from Kt =1.5 to 2.5. Fatigue Life increased with increasing stress concentration under pure cyclic torsion, while it decreased with increasing stress concentration under cyclic torsion with static tension. From the measurement of fatigue Crack initiation and Propagation lives using electric potential drop method, it was found that the Crack initiation Life decreased with increasing stress concentration and the Crack Propagation Life increased with increasing stress concentration under pure cyclic torsion. Under cyclic torsion with static tension, the Crack initiation Life also decreased with increasing stress concentration but the Crack Propagation Life decreased or not changed with increasing stress concentration then the total fatigue Life of sharper notched specimen decreased. It was also found that the fatigue Life of smooth specimen under cyclic torsion with static tension was longer than that under pure cyclic torsion. This behavior could be explained based on the cyclic strain hardening under non-proportional loading and the difference in Crack path with and without static tension.Copyright © 2010 by ASME

Toshiyuki Ishikawa - One of the best experts on this subject based on the ideXlab platform.

  • fatigue Crack Propagation analysis for welded joint subjected to bending
    International Journal of Fatigue, 2011
    Co-Authors: Biehn Baik, Kentaro Yamada, Toshiyuki Ishikawa
    Abstract:

    Abstract In this paper, fatigue tests have been conducted on specimens, which are flat plate with a notch, stud-welded plate, T-shaped fillet welded joint and cruciform fillet welded joint, in such a way that fatigue Cracks could be initiated and propagated in bending load. Under bending load, surface Crack has formed flat semi-ellipse and propagated to about 80% of plate thickness before failure. Besides, the fatigue Crack Propagation Life of Cracked welded joint specimen has been predicted using fracture mechanics method. In particular, a correction factor equation has been developed for covering linearly varying stress distribution along Crack Propagation path under bending load. This equation has been applied to calculating stress intensity factor (SIF) in relation to fatigue Life prediction.

Youngsik Choi - One of the best experts on this subject based on the ideXlab platform.

  • influence of rake angle on surface integrity and fatigue performance of machined surfaces
    International Journal of Fatigue, 2015
    Co-Authors: Youngsik Choi
    Abstract:

    Abstract This study investigates the influence of the feed rate on the surface integrity and fatigue performance of machined surfaces. The results demonstrate that a higher feed rate increases Crack initiation Life and Crack Propagation Life. A higher feed rate induces more compressive residual stresses and a more softened layer. The feed rate influences Crack initiation Life up to 45% and Crack Propagation Life up to 149%. Consequently, the feed rate affects fatigue Life up to 132%. The fatigue tests substantiate that the feed rate influences fatigue Life significantly and that the effect increases significantly if the loading is reduced.

  • a new methodology for predicting Crack initiation Life for rolling contact fatigue based on dislocation and Crack Propagation
    International Journal of Mechanical Sciences, 2008
    Co-Authors: Youngsik Choi
    Abstract:

    Abstract A new methodology for predicting Crack initiation Life is presented and validated experimentally. The methodology considers that the total fatigue Life is the summation of Crack initiation Life and Crack Propagation Life, since fatigue failures are due to Crack initiation and Crack Propagation. It has been established that the Crack Propagation Life can be estimated based on a modified Paris’ law when the size of Crack is larger than a certain value. However, there has been no verified method for estimating the Crack initiation Life with good accuracy. The proposed methodology for predicting the Crack initiation Life is based on a dislocation model, and the constants for the model are determined by the Crack initiation lives obtained by a new approach. This new approach determines the Crack initiation Life by subtracting the predicted Crack Propagation Life from the experimentally obtained total fatigue Life. The developed Crack initiation Life model is combined with a Crack Propagation Life model for the prediction of fatigue Life. It is noted that the standard deviation in the ratios of experimental Life to predicted Life by the developed fatigue Life model is only 14% of that by the International Standard.

Naeem Ul Haq Tariq - One of the best experts on this subject based on the ideXlab platform.

  • very high cycle fatigue behavior of bearing steel with rare earth addition
    International Journal of Fatigue, 2020
    Co-Authors: Chaoyun Yang, Naeem Ul Haq Tariq, Yikun Luan, Dianzhong Li, Yiyi Li
    Abstract:

    Abstract This study aims to clarify the effect of rare earth (RE) addition on the very high cycle fatigue (VHCF) behavior of high-carbon chromium bearing steel. For this purpose, ultrasonic tension-compression fatigue tests were carried out on specimens extracted from bearing steels with and without RE addition. As a result, RE addition can prolong the fatigue Life of bearing steel over 10 times and improve the fatigue limit at 109 cycles by 9.4% from 720 MPa to 788 MPa, which mainly result from the modification of RE elements to common CaO-Al2O3-MgO-SiO2-CaS inclusions, forming complex RE inclusions and leading to the decrease of inclusion size and the volume fraction of inclusions in bearing steel with RE addition. On the VHCF fracture of bearing steels with and without RE addition, both internal Cracking mode and interface Cracking mode exist at inclusions. Compared with bearing steel with RE addition, bearing steel without RE addition exhibits a longer Crack initiation Life due to stronger internal binding force of complex inclusions and interfacial binding force between complex inclusions and the matrix. However, smaller complex RE inclusions make Crack Propagation Life of the former significantly longer than that of the latter. In addition, fine granular area (FGA) can be used to estimate the fatigue limit of different fatigue Life in the VHCF regime and the fatigue limit at 109 cycles evaluated based on FGA indicates an error of around 2% with respect to the fatigue limit measured by staircase method.

Filippo Berto - One of the best experts on this subject based on the ideXlab platform.

  • averaged strain energy density based synthesis of Crack initiation Life in notched steel bars under torsional fatigue
    Fracture and Structural Integrity, 2016
    Co-Authors: Filippo Berto, Alberto Campagnolo, Giovanni Meneghetti, Keisuke Tanaka
    Abstract:

    The torsional fatigue behaviour of circumferentially notched specimens made of austenitic stainless steel, SUS316L, and carbon steel, SGV410, characterized by different notch root radii has been recently investigated by Tanaka. In that contribution, it was observed that the total fatigue Life of the austenitic stainless steel increases with increasing stress concentration factor for a given applied nominal shear stress amplitude. By using the electrical potential drop method, Tanaka observed that the Crack nucleation Life was reduced with increasing stress concentration, on the other hand the Crack Propagation Life increased. The experimental fatigue results, originally expressed in terms of nominal shear stress amplitude, have been reanalysed by means of the local strain energy density (SED) averaged over a control volume having radius R0 surrounding the notch tip. To exclude all extrinsic effects acting during the fatigue Crack Propagation phase, such as sliding contact and/or friction between fracture surfaces, Crack initiation Life has been considered in the present work. In the original paper, initiation Life was defined in correspondence of a 0.1÷0.4-mm-deep Crack. The control radius R0 for fatigue strength assessment of notched components, thought of as a material property, has been estimated by imposing the constancy of the averaged SED for both smooth and Cracked specimens at NA = 2 million loading cycles. KEYWORDS. Torsional fatigue; Notch effect; Crack initiation; Averaged SED; Electrical potential drop

  • synthesis of Crack initiation Life in steel notched specimens under torsional fatigue based on the averaged strain energy density
    Procedia structural integrity, 2016
    Co-Authors: Alberto Campagnolo, Giovanni Meneghetti, Filippo Berto, Keisuke Tanaka
    Abstract:

    Abstract The torsional fatigue behaviour of circumferentially notched specimens made of austenitic stainless steel, SUS316L, and carbon steel, SGV410, characterized by different notch root radii has been recently investigated by Tanaka. In that contribution, it was observed that the total fatigue Life of the austenitic stainless steel increases with increasing stress concentration factor for a given applied nominal shear stress amplitude. By using the electrical potential drop method, Tanaka observed that the Crack nucleation Life was reduced with increasing stress concentration, on the other hand the Crack Propagation Life increased. The experimental fatigue results, originally expressed in terms of nominal shear stress amplitude, have been reanalysed by means of the local strain energy density (SED) averaged over a control volume having radius R 0 surrounding the notch tip. To exclude all extrinsic effects acting during the fatigue Crack Propagation phase, such as sliding contact and/or friction between fracture surfaces, Crack initiation Life has been considered in the present work (*). In the original paper, initiation Life was defined in correspondence of a 0.1÷0.4-mm-deep Crack. The control radius R 0 for fatigue strength assessment of notched components, thought of as a material property, has been estimated by imposing the constancy of the averaged SED for both smooth and Cracked specimens at N A = 2 million loading cycles. (*) A version of the present contribution has already been presented at the 11 th International Conference on Multiaxial Fatigue and Fracture (ICMFF11).

  • Averaged strain energy density-based synthesis of Crack initiation Life in notched steel bars under torsional fatigue
    Gruppo Italiano Frattura, 2016
    Co-Authors: Filippo Berto, Alberto Campagnolo, Giovanni Meneghetti, Keisuke Tanaka
    Abstract:

    The torsional fatigue behaviour of circumferentially notched specimens made of austenitic stainless steel, SUS316L, and carbon steel, SGV410, characterized by different notch root radii has been recently investigated by Tanaka. In that contribution, it was observed that the total fatigue Life of the austenitic stainless steel increases with increasing stress concentration factor for a given applied nominal shear stress amplitude. By using the electrical potential drop method, Tanaka observed that the Crack nucleation Life was reduced with increasing stress concentration, on the other hand the Crack Propagation Life increased. The experimental fatigue results, originally expressed in terms of nominal shear stress amplitude, have been reanalysed by means of the local strain energy density (SED) averaged over a control volume having radius R0 surrounding the notch tip. To exclude all extrinsic effects acting during the fatigue Crack Propagation phase, such as sliding contact and/or friction between fracture surfaces, Crack initiation Life has been considered in the present work. In the original paper, initiation Life was defined in correspondence of a 0.1÷0.4-mm-deep Crack. The control radius R0 for fatigue strength assessment of notched components, thought of as a material property, has been estimated by imposing the constancy of the averaged SED for both smooth and Cracked specimens at NA = 2 million loading cycle