PSI - Issue 23

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

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ScienceDirect

Procedia Structural Integrity 23 (2019) 245–250

© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers © 201 9 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. Multiscale mechanisms of fatigue damage-failure transitions in m tals r s udi d for High Cycle and V ry Hi h Cycle Fatigue and analyz d as duality of inherently linked two typ s of singulariti s related to the singularity of multis ale damag k etics under crack nucleation and singularity of stre s field at the crack tip as the classical framework of fracture m chanics. The singularity of multiscale damage kinetics was establish d as natural precursor of crack nucleation and specific non ine rity (m tastability) of fre en rgy rel ase in erm of damage parameter (defec induced strain). Experimentally estimated scales and pow r exponents were used in the constitutive laws of crack advance as the structure sensitive parameters for characteristic damage-failure transition stages. © 201 9 The Authors. Published by Elsevier B.V. This is an ope acces article under CC BY-NC-ND lic nse (http://creativecommon org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. Multiscale mechanisms of fatigue damage-failure transitions in metals are studied for High Cycle and Very High Cycle Fatigue and analyzed as duality of inherently linked two types of singularities related to the singularity of multiscale damage kinetics under crack nucleation and singularity of stress field at the crack tip as the classical framework of fracture mechanics. The singularity of multiscale damage kinetics was established as natural precursor of crack nucleation and specific nonlinearity (metastability) of free energy release in term of damage parameter (defect induced strain). Experimentally estimated scales and power exponents were used in the constitutive laws of crack advance as the structure sensitive parameters for characteristic damage-failure transition stages. 9th International Conference on Materials Structure and Micromechanics of Fracture Defects induced multiscale kinetics of damage-failure transition under very high cycle fatigue Oleg Naimark * Institute of Continuous Media Mechanics UB RAS, 1 Acad.Korolev ctr., 614013 Perm Russia 9th International Conference on Materials Structure and Micromechanics of Fracture Defects induced multiscale kinetics of damage-failure transition under very high cycle fatigue Oleg Naimark * Institute of Continuous Media Mechanics UB RAS, 1 Acad.Korolev ctr., 614013 Perm Russia Abstract Abstract

Keywords: multiscale damage kinetics; VHCF; defect induced criticality Keywords: multiscale damage kinetics; VHCF; defect induced criticality

1. Introduction 1. Introduction

High (HCF) and Very High Cycle (VHCF) Fatigue are a major fundamental and engineering problems for various applications. Sustained interest in VHCF (10 8 -10 9 cycles) is associated with progress in creating new (nano- and submicro-crystalline) materials, breakthrough trends in technology, which ensured the economic demand for the giga- High (HCF) and Very High Cycle (VHCF) Fatigue ar a major fundamental and engineering problems for various applications. Sustained intere t in VHCF (10 8 -10 9 cycles) is associated with progress i creating new (nano- and submicro-crystalline) materials, breakthrough trends in technology, which ensured the economic demand for the giga-

* Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address: naimark@icmm.ru * Correspon ing author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address: naimark@icmm.ru

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an ope acces article under CC BY-NC-ND lic nse (http://creativecommon org/licenses/by-nc-nd/4.0/)

Peer-review under responsibility of the scientific committee of the IC MSMF organizers.

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers 10.1016/j.prostr.2020.01.094