PSI - Issue 30

Available online at www.sciencedirect.com Available online at www.sciencedirect.com Sci nceD rect Structural Integrity Procedia 00 (2020) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2020) 000–000

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Procedia Structural Integrity 30 (2020) 120–127

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Abstract A review of the fracture mechanics problems for estimating the safety of constructions with the crack-like defects is carried out. The need to develop a new methodology that combines the advantages of calculation and instrumental methods was revealed. The correlations between the most important fracture mechanics parameters and the characteristics of acoustic-emission signals proposed to use for estimating the parameters of stress-strain state. It is noted that considerable attention should be paid to the size and shape of the plastic zone in order to establish a theoretical relationship between the characteristics of acoustic signals and the fracture mechanics parameters. It is assumed that T-stresses are the cause of differences in the coefficients of the power dependence of the parameters of acoustic signals for the same values of the stress intensity factor. The task of finding the influence of T-stresses on the size of the plastic zone at the crack tip is set. A numerical modeling of thermal loading of a steel sheet with a central crack by the finite element method is carried out in order to determine the dependence of the crack tip plastic zone size on the stress intensity factor for several values of T-stress. Multiple calculations of the stress intensity factor and the T stresses were performed for the several values of the cooling zone, using the parametric design language ANSYS APDL. By substituting the yield point of the material into the equations of linear elastic fracture mechanics, the specific volume and linear plastic zone size along the crack line were determined for the previously found values of the stress intensity factor and T-stress. A relationship between the fracture mechanics parameters and the plastic zone size at the crack tip was established using numerical methods. The assumptions that the T-stress influence to the plastic zone size are qualitatively confirmed. It is shown, that the negative values of T-stresses decrease the plastic zone size for a same value of the stress intensity factor. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Keywords: Plastic zone, T-stress, Stress intensity factor, acoustic-emission control. Abstract A review of the fracture mechanics problems for estimating the safety of constructions with the crack-like defects is carried out. The n ed to d velop a new methodol gy that combines the adv ntages of calc lation and instrumental method was evealed correlations betwee the most important fracture mec anics parameters nd the ch racteristics of cous ic-emission signals proposed to use for estimating the parameters of st ss-strai state. It is noted that considerable attention should be paid to the size and shape o th plastic zon in ord r to establi h a theoretical relati nship between the ch racteristics f acoustic signals and the fracture mechanics parameters. It is assumed t t T-st sses ar the cause of differences in th coefficients of he power dependence of the parameters of acous ic signals for the same valu s of the stress intensity fac or. The task of inding the influence of T-s r sses on the size of the plastic zone at the crack tip is set. A num rical modeling f thermal loading of a steel sheet with a cen al crack by the finite elemen method is carried out in order to determine the dependenc of the crack tip plastic zon size on the stress intensity factor for s veral values of T-stress. Multiple calculatio s of the stress intensi y factor and the T stresses were p rformed for he several valu s of the c oling zone, using the par metric design language ANSYS APDL. By ub tituting the yield point of the material into the equati ns of li ar elastic fracture me hanics, the specific volume and linear pla tic zo e size along the crack line were determined for the previously found valu s of t e stress intensity factor and T-stress. A relati ship between the fractur m chanics parameters and the plastic zone size a the crack tip was established using numerical methods. The assumptions that the T-stress influence to the plastic re qualit tively confirmed. It is show , that the negative values of T-stresses decreas the pla t c zone size for a s me valu of the stress intensit facto . © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review u der responsibility of EURASTRE COLD - 2020 guest editors K ywords: Plastic zon , T-stress, Stress intensity factor, acoustic-emission control. IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) The T-stress influence on the plastic zone size around the crack tip under the thermal load IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) The T-stress influence on the plastic zone size around the crack tip under the thermal load Prokopyev L.A. a, *, Andreev Y.M. a , Lukin E.S. b , Bolshakov A.M. b a Federal Research Centre “The Yakut Scientific Centre SB RAS”, 2 Petrovskogo St., Yakutsk, 677980, Russia b Larionov Institute of Physical-Technical Problems of the North SB RAS, 1 Oktyabrskaya St., Yakutsk, 677980, Russia Prokopyev L.A. a, *, Andreev Y.M. a , Lukin E.S. b , Bolshakov A.M. b a Federal Research Centre “The Yakut Scientific Centre SB RAS”, 2 Petrovskogo St., Yakutsk, 677980, Russia b Larionov Institute of Physical-Technical Problems of the North SB RAS, 1 Oktyabrskaya St., Yakutsk, 677980, Russia

* Corresponding author. Tel.: +79681548286. E-mail address: l.prokopyev@yandex.ru * Corresponding author. Tel.: +79681548286. E-mail address: l.prokopy v@yandex.ru

2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of the EURASTRENCOLD - 2020 guest editors 2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review u der the responsibility of the EURASTRENCOLD - 2020 gu st editors

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors 10.1016/j.prostr.2020.12.035