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

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 23 (2019) 63–68

© 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. Based on the concept of physic l mesomechanics, e sequence of damage accumulation mechanisms was c nsidered in accord ce with stress lev l increasing. It was shown that metals ehavior evolution takes place in the direction fro micro- to meso- and then acroscale level in ccordance with introduced bi urcation diagram. It was explained why metals mechanical characteris c nam d “fatig e limit” cannot be used for simulation of structure durability and in -service lifetime. The problem of bimodal fatigue life distribution for different types of metals was discussed when b fur ation transit on from o e to another scale level of metals e olution takes place. Test data for “fatigue limit” deter ination in accordance with the standard technique of more than 25 0 aviation structural materials were eviewed. Influence of mechanical characteristics on the “fatigue limit” value was analyzed. It as d monstrated that the major part of m terials realized all h e scale level during str ss level incre sing. Realization of low-cycle-fatigue is not designed case for operating complex structures when the mesoscale level of metal fatigue does not exist. © 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. 9th International Conference on Materials Structure and Micromechanics of Fracture The fatigue limit of metals as a characteristic of the multimodal fatigue life distribution for structural materials A.A. Shanyavskiy a,b *, A.P. Soldatenkov a a Aviation Register for Russian Federation, Airport Sheremetievo-1, PO Box 54, Moscow region, Chimkinskiy State, 141426, Russia b Institute of Computer Aided Design, 2nd Brestskaya street 19/18, Moscow, 123056, Russia Based on the concept of physical mesomechanics, the sequence of damage accumulation mechanisms was considered in accordance with stress level increasing. It was shown that metals behavior evolution takes place in the direction from micro- to meso- and then macroscale level in accordance with introduced bifurcation diagram. It was explained why metals mechanical characteristic named “fatigue limit” cannot be used for simulation of structure durability and in -service lifetime. The problem of bimodal fatigue life distribution for different types of metals was discussed when bifurcation transition from one to another scale level of metals evolution takes place. Test data for “fatigue limit” determination in accordance with the standard technique of more than 25 0 aviation structural materials were reviewed. Influence of mechanical characteristics on the “fatigue limit” value was analyzed. It was demonstrated that the major part of materials realized all three scale level during stress level increasing. Realization of low-cycle-fatigue is not designed case for operating complex structures when the mesoscale level of metal fatigue does not exist. 9th International Conference on Materials Structure and Micromechanics of Fracture The fatigue limit of metals as a characteristic of the multimodal fatigue life distribution for structural materials A.A. Shanyavskiy a,b *, A.P. Soldatenkov a a Aviation Register for Russian Federation, irport Sheremetievo-1, PO Box 54, Moscow region, Chimkinskiy State, 141426, Russia b Institute of Computer Aided Design, 2nd Brestskaya street 19/18, Moscow, 123056, Russia Abstract Abstract

Keywords: metals; fatigue; scale levels; bimodal distribution; bifurcation; crack origination; subsurface; mechanisms Keywords: metals; fatigue; scale levels; bimodal distribution; bifurcation; crack origination; subsurface; mechanisms

* Corresponding author. Tel.: +7-495-578-5288; fax: +7-495-730-6094. E-mail address: 106otdel@mail.ru * Correspon ing auth r. Tel.: +7-495-578-5288; fax: +7-495-730-6094. E-mail address: 106otdel@mail.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.2020.01.064