PSI - Issue 47

ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

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

Procedia Structural Integrity 47 (2023) 646–653

© 2023 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 IGF27 chairpersons Abstract In this study, tensile tests are performed on notched flat specimens to calibrate the Gurson-Tvergaard-Needleman (GTN) model for a selected VVER440 material and the optimization of damage parameters using artificial neural networks (ANN) is presented. The specified parameters are applied to standard Compact Tension (CT) specimens, whose fracture behavior is used to estimate the fracture toughness (geometry independent) material properties with finite element simulation software. In order to compare fracture toughness simulations conducted by means of the classical fracture mechanics approach based on J-Integral, detailed local approach analyses are performed on CT specimens. In the determination of fracture toughness, a new approach is used, the crack propagation is based on the virtual crack closure technique (VCCT), as this allows the calculation of the J-integral in the software during the crack propagation. The results indicate that the new approach gives similar fracture toughness compared to the conventional method and measured values, but with significantly higher computational efficiency. © 2023 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 IGF27 chairpersons Keywords: GTN model; ANN method; VCCT; fracture toughness; fracture mechanics 1. Introduction The method for determining the long-term safe operation of nuclear power plants is based on a systematic ageing management procedure. A crucial part of this process is to demonstrate the integrity of nuclear power plant 27th International Conference on Fracture and Structural Integrity (IGF27) Simulation of crack propagation using a GTN ductile damage model based on the virtual crack closure technique Zoltán Bézi a * , Bernadett Spisák a,b , Réka Erdei a , Szabolcs Szávai a,b a Bay Zoltán Nonprofit Ltd. for Applied Research, Iglói str. 2 ., Miskolc H-3519, Hungary b University of Miskolc, Egyetemváros, Miskol c H-3515, Hungary Abstract In this study, tensile tests are performed on notched flat specimens to calibrate the Gurson-Tvergaard-Needleman (GTN) model for a selected VVER440 material and the optimization of damage parameters using artificial neural networks (ANN) is presented. The specified parameters are applied to standard Compact Tension (CT) specimens, whose fracture behavior is used to estimate the fracture toughness (geometry independent) material properties with finite element simulation software. In order to compare fracture toughness simulations conducted by means of the classical fracture mechanics approach based on J-Integral, detailed local approach analyses are performed on CT specimens. In the determination of fracture toughness, a new approach is used, the crack propagation is based on the virtual crack closure technique (VCCT), as this allows the calculation of the J-integral in the software during the crack propagation. The results indicate that the new approach gives similar fracture toughness compared to the conventional method and measured values, but with significantly higher computational efficiency. © 2023 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 IGF27 chairpersons Keywords: GTN model; ANN method; VCCT; fracture toughness; fracture mechanics 1. Introduction The method for determining the long-term safe operation of nuclear power plants is based on a systematic ageing management procedure. A crucial part of this process is to demonstrate the integrity of nuclear power plant 27th International Conference on Fracture and Structural Integrity (IGF27) Simulation of crack propagation using a GTN ductile damage model based on the virtual crack closure technique Zoltán Bézi a * , Bernadett Spisák a,b , Réka Erdei a , Szabolcs Szávai a,b a Bay Zoltán Nonprofit Ltd. for Applied Research, Iglói str. 2 ., Miskolc H-3519, Hungary b University of Miskolc, Egyetemváros, Miskol c H-3515, Hungary

* Corresponding author. Tel.: +36-70-515-7108 E-mail address: zoltan.bezi@bayzoltan.hu * Corresponding author. Tel.: +36-70-515-7108 E-mail address: zoltan.bezi@bayzoltan.hu

2452-3216 © 2023 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 IGF27 chairpersons 2452-3216 © 2023 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 IGF27 chairpersons

2452-3216 © 2023 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 IGF27 chairpersons 10.1016/j.prostr.2023.07.057