PSI - Issue 48

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000 – 000

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

ScienceDirect

Procedia Structural Integrity 48 (2023) 326–333

© 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 IRAS 2023 organizers Abstract The use of miniaturized specimen test methods is a promising way to overcome the limited materials problem of RPV monitoring programs. The use of small specimens allows the evaluation of fracture toughness from other specimen materials used. In particular, the small size compact tensile specimen (0.16 CT, 4 mm thickness) is promising for fracture toughness determination as it can be produced from the already tested standard size Charpy specimen. The aim of this paper is to demonstrate the feasibility of fracture toughness testing using small sized specimens. For this local approach modeling method was applied. The necessary damage parameters were determined with the help of artificial neural networks, which parameters later were implemented into the modified virtual crack closure technique. The novelty of the research is that the improved simulation method can be used to determine the fracture toughness of the material with good accuracy even for small specimens. © 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 IRAS 2023 organizers Keywords: Virtual Crack Closure Technique; Gurson-Tvergaard-Needleman; J-integral; Charpy specimen 1. Introduction Knowledge of the mechanical properties of the structural materials of power plant components is an essential factor for reliable integrity assessments and accurate residual life predictions. Especially in cases, where brittleness and degradation of structural materials is caused by exposure to neutron irradiation, high temperatures or aggressive Second International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023) Modification of VCCT method with implementation of GTN model for the determination of J -integral Bernadett Spisák a,b, *, Zoltán Bézi a , Réka Erdei a , Szabolcs Szávai a,b a Bay Zoltán Nonprofit Ltd. for Applied Research, Iglói street 2., Miskolc 3519, Hungary b University of Miskolc, Egyetemváros, Miskolc 3515, Hungary Abstract The use of miniaturized specimen test methods is a promising way to overcome the limited materials problem of RPV monitoring programs. The use of small specimens allows the evaluation of fracture toughness from other specimen materials used. In particular, the small size compact tensile specimen (0.16 CT, 4 mm thickness) is promising for fracture toughness determination as it can be produced from the already tested standard size Charpy specimen. The aim of this paper is to demonstrate the feasibility of fracture toughness testing using small sized specimens. For this local approach modeling method was applied. The necessary damage parameters were determined with the help of artificial neural networks, which parameters later were implemented into the modified virtual crack closure technique. The novelty of the research is that the improved simulation method can be used to determine the fracture toughness of the material with good accuracy even for small specimens. © 2023 The Authors. Published by ELSEVIER B.V. Keywords: Virtual Crack Closure Technique; Gurson-Tvergaard-Needleman; J-integral; Charpy specimen 1. Introduction Knowledge of the mechanical properties of the structural materials of power plant components is an essential factor for reliable integrity assessments and accurate residual life predictions. Especially in cases, where brittleness and degradation of structural materials is caused by exposure to neutron irradiation, high temperatures or aggressive Second International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023) Modification of VCCT method with implementation of GTN model for the determination of J -integral Bernadett Spisák a,b, *, Zoltán Bézi a , Réka Erdei a , Szabolcs Szávai a,b a Bay Zoltán Nonprofit Ltd. for Applied Research, Iglói street 2., Miskolc 3519, Hungary b University of Miskolc, Egyetemváros, Miskolc 3515, Hungary

* Corresponding author. Tel.: +36-70/709-3675; E-mail address: bernadett.spisak@bayzoltan.hu * Corresponding author. Tel.: +36-70/709-3675; E-mail address: bernadett.spisak@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 IRAS 2023 organizers 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 IRAS 2023 organizers

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 IRAS 2023 organizers 10.1016/j.prostr.2023.07.125