PSI - Issue 42

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

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Procedia Structural Integrity 42 (2022) 1350–1360

© 2022 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 scientific committee of the 23 European Conference on Fracture – ECF23 Abstract This paper addresses the narrow applicable fracture toughness range of the master curve method (ASTM-E1921) by expanding the scaling process to include the effect of constraint loss in miniaturized specimens. To facilitate the acquisition and scalability of reliable fracture toughness data from one specimen size to another and to apply the Master-Curve method with confidence when using small specimens, the difference in the structure of the crack tip stress field between large and small specimens has to be well understood and modeled. In this study, the crack tip stresses of two specimen sizes (1T and 0.18T compact tension specimens) were calculated with 3D finite element simulations run over a range of loadings (or equivalently for a range of constraint levels) and at different temperatures in the lower part of the ductile to brittle transition of a structural steel. The toughness scaling, based on a local approach to brittle fracture, is compared with the pure statistical correction of the crack front length recommended in the ASTM standard E1921. We show that the effect of constraint loss already becomes significant at low K Jc values. Consequently, we propose a simple “modified correction factor”, k M , based on the ratio of crack front length and critical area/volume, accounting for constraint loss. Applying this correction factor, we show that scaling between specimen sizes and geometries yields very good correlation between simulated and scaled/calculated stress intensities. © 2020 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 23 European Conference on Fracture - ECF23 Keywords: Finite Element Analysis; Nuclear Reactor Safety; Fracture Mechanics; Brittle Fracture; Constraint Loss; Miniaturization quisition a © 2020 The Author This is an open access ar 23 European Conference on Fracture - ECF23 Analysis of crack front loading to improve reliability of fracture toughness calculations based on miniaturized CT specimens B.Aydin Baykal a, *, Philippe Spätig a a1 Laboratory for Nuclear Materials, Paul Scherrer Institut, Forschungstrasse 111 5232 Villigen PSI, Aargau, Switzerland

* Corresponding author. Tel.: +41 56 310 36 54. E-mail address: bedi.baykal@psi.ch

2452-3216 © 2020 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 23 European Conference on Fracture - ECF23

2452-3216 © 2022 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 scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.172