PSI - Issue 18

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect

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Procedia Structural Integrity 18 (2019) 608–615

25th International Conference on Fracture and Structural Integrity Experimental and theoretical analysis of heat flux at fatigue crack tip under mixed mode loading A. Vshivkov a *, A. Iziumova a , R. Yarullin b , V. Shlyannikov b , O. Plekhov a a Institute of Continuous Media Mechanics Russian Academy of Sciences Ural Branch, Academika Koroleva st, 1, Perm, 614013, Russian Federation b Institute of Power Engineering and Advanced Technologies, FRC Kazan Scientific Center, Russian Academy of Sciences, Lobachevskogo str. 2/31, Kazan, 420111, Russian Federation Abstract The work is devoted to experimental and theoretical study of heat dissipation at the fatigue crack tip during mixed mode loading. The plane samples of stainless steel (AISI 304) were weakened by notch to initiate fatigue crack. There were two types of samples for uniaxial loading and biaxial loading. Infrared thermography and the contact heat flux sensor based on the Seebeck effect were used to measure the dissipated thermal energy. The samples were subject to cyclic loading with constant stress amplitude and different biaxial coefficients. The experimental results confirmed the hypothesis about two stages of heat dissipation at fatigue crack tip under Paris regime. At the first stage, the power of heat flux is proportional to the product of the crack rate by the crack length. The second stage is characterized by a traditional linear relationship between the crack rate and the heat flux. The theoretical approach to calculate dissipation energy at fatigue crack tip was obtained. This technique based on link between the elastic-plastic and elastic strain fields at crack tip using the coupling between Young’s modulus and the secant plasticity modulus. 25th International Conference on Fracture and Structural Integrity Experimental and theoretical analysis of heat flux at fatigue crack tip under mixed mode loading A. Vshivkov a *, A. Iziumova a , R. Yarullin b , V. Shlyannikov b , O. Plekhov a a Institute of Continuous Media Mechanics Russian Academy of Sci nces Ural Branch, Academika Koroleva st, 1, Perm, 614013, Russian Federation b Institute of Power Engineering and Advanced Technologies, FRC Kazan Scientific Cen er, Russian Academy of Sciences, Lobachevskogo str. 2/31, Kazan, 420111, Russian Federation Abstract work is devoted to experimental and theoretical study of heat dissipatio at the fatigue crack tip during mixed mode loading. The plane samples of stainless steel (AISI 304) wer weakened by notch t initiat fatigue crack. Th re were two types of samples for uniaxial loading and biaxial loading. I frared t ermography and the contact heat flux sensor based on the Seebeck effect were used to me sure th dissipated thermal en rgy. The samples were subject to cyclic loading with c nstant stress amplitude and different biaxial coefficients. The xperimental r sults confirmed the hyp thesis about two stages f heat dissipation at fatigue crack tip under Paris regime. At the first stage, the power of heat flux is roportio al to the product of the crack rate by the crack length. The second stage is characterized by traditional linear relationship between the crack rate and the heat flux. The theoretical approach to calculate dissipation energy at fatigue crack tip was obtained. This technique based on link between the elastic-plastic and elastic strain fields at crack tip using the coupling between Young’s modulus and the secant plasticity modulus.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

Keywords: fatigue; crack; deformation; biaxial loading; Keywords: fatigue; crack; deformation; biaxial loading;

1. Introduction A number of approaches has been developed to study the processes of nucleation and propagation of fatigue cracks in metals [1-4]. Under deformation, the structural changes are observed at all scale levels and leads to irreversible 1. Introduction A number of approaches has been developed to study the processes of nucleation and propagation of fatigue cracks in metals [1-4]. Under deformation, the structural changes are observed at all scale levels and leads to irreversible

* Corresponding author. Tel.: +73422378312; E-mail address: vshivkov.a@icmm.ru * Correspon ing aut or. Tel.: +73422378312; E-mail address: vshivkov.a@icmm.ru

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.206