PSI - Issue 42

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

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 42 (2022) 672–679

23 European Conference on Fracture - ECF23 Damage Assessment for Steel Structures Subjected to cyclic pre-strain Rafael Magalhães de Melo Freire a , Naoya Oie a , Tomoya Kawabata a * a The University of Tokyo, 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656, Japan Subjected

© 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 Plastic deformation provoked by unexpected events, such as earthquakes, can deteriorate the steel fracture toughness, and it can also induce premature failure of a structure and accidents. This study tries to formulate new equations to quantify the fracture toughness degradation of steel that was cyclic pre-strained. Four point bending tests were used to carry out the cyclic plastic pre strain and Crack Tip Opening Displacement (CTOD) tests were conducted to compare pre-strained specimens with the steel without plastic deformation (as-received). The cumulative damage law was employed to account for the difference between each specimen, associated with Weibull stresses and critical CTOD values. Furthermore, additional Finite Element Method (FEM) simulations were conducted, using the new approach for the establishment an accurate Weibull Stress criterion, which can represent different cleavage fracture resistance according to the last pre-strain cycle. In the end, a new CTOD equation was also formulated using macro parameters, and it can account for the fracture toughness degradation of material that was subjected to cyclic plastic deformation. © 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/) Plastic deformation provoked by unexpected events, such as earthquakes, can deteriorate the steel fracture toughness, and it can This is an open access article under the CC B

Peer-review under responsibility of 23 European Conference on Fracture - ECF23 Keywords: Cyclic pre-strain; fracture toughness; Weibull stress; critical CTOD; earthquakes;

1. Introduction The phenomenon of brittle fracture has been investigated for years and it is important in the prevention of accidents with steel structures. Fracture toughness can vary or suffer with degradation due to many factors, such as low

* Corresponding author. Tel.: +81-3-5841-6517; fax: +0-000-000-0000 . E-mail address: rafael@fract.t.u-tokyo.ac.jp

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.2022.12.085