PSI - Issue 20

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

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ScienceDirect

Procedia Structural Integrity 20 (2019) 30–36

1st International Conference on Integrity and Lifetime in Extreme Environment (ILEE-2019) TCD-based criteria for quasi-brittle fracture of materials and structures S.V. Suknev a, * a Chersky Institute of Mining of the North SB RAS, Lenin Ave, 43, Yakutsk 677980, Russia Abstract Nonlocal fracture criteria, recently developed within the framework of the theory of critical distances, are analyzed. It is marked that the scope of application is limited to cases of brittle or quasi-brittle fracture with a small fracture process zone. To expand the scope of the criteria for cases of fracture with a developed fracture process zone, it is proposed to abandon the hypothesis of the size of this zone as a material constant, associated only with the microstructure of the material. New nonlocal criteria for quasi-brittle fracture are proposed, which are the development of the average stress criterion, and point stress criterion, and which contain a complex parameter that characterizes the size of the fracture process zone and accounts not only for the material microstructure, but also plastic properties of the material, geometry of the specimen, and its loading conditions. Formulae for critical stress in the problems of the fracture of plates with a circular hole in uniaxial tension and compression are obtained. Calculation results are in good agreement with experimental data. 1st International Conference on Integrity and Lifetime in Extreme Environment (ILEE-2019) TCD-based criteria for quasi-brittle fracture of materials and structures S.V. Suknev a, * a Chersky Institute of Mining of the North SB RAS, Lenin Ave, 43, Yakutsk 677980, Russia Abstract Nonlocal fracture criteria, recently d veloped within the framework of the theory of critical distances, are analy ed. It is marke t at the scope of application i limited to cases of brittle or quasi-b ittle fracture with a small fracture process zone. To xpand t cope of the criteria for cases of fracture with a d veloped fracture process zone, it is propos d to abandon the hypothesis of the size of this zone as a material const nt, associated only wit the micro tructu e of the material. N w nonlocal criteria for quasi-brittle fracture e proposed, w ich are the development of the average stre s crit rion, nd point stress criterion, and which contain a complex parameter that characterizes the size of the f acture process zone and accounts n t only for the m terial microstructure, but als plastic properties of the m t rial, geometry of the specimen, and its lo ding conditions. Formul e for critical stress in the problems of the fracture of plates with a circular hole in uniaxial tension and compression are obtained. Calculation results are in good agreement with experimental data.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers © 2019 The Author( ). Publ shed by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers

Keywords: Quasi-Brittle fracture; Nonlocal fracture criteria; TCD; Size effect; Circular hole. Keywords: Quasi-Brittle fracture; Nonlocal fracture criteria; TCD; Size effect; Circular hole.

1. Introduction Integrity of structures containing defects and stress risers is evaluated using nonlocal fracture criteria, based on the concept of the formation of a fracture process zone (FPZ) in the material, in which there is local redistribution of stresses, whereas the main material is deformed elastically until failure. 1. Introduction Integrity of structures containing defects and stress risers is evaluated using nonlocal fracture criteria, based n the concept of the for ation of a fracture process zone (FPZ) in the material, in which there is local redistribution of stresses, whereas the main material is deformed elastically until failure.

2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers 2452-3216 © 2019 Th Author(s). Publis d by lsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers * Corresponding author. Tel.: +7-4112-39-0694; Fax: +7-4112-33-5930. E-mail address: suknyov@igds.ysn.ru * Corresponding author. Tel.: +7-4112-39-0694; Fax: +7-4112-33-5930. E-mail address: suknyov@igds.ysn.ru

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers 10.1016/j.prostr.2019.12.111