PSI - Issue 42

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ScienceDirect

Procedia Structural Integrity 42 (2022) 1676–1683 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 0 (20 9) 000–000

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© 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 © 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: Very high cycle fatigue; Structural steel; Ultrasonic testing Abstract Testing beyond 10 millions of cycles in a conventional fatigue machine is a very time consuming task, so the fatigue limit has been settled around this number of cycles. However, during the service life, several engineering components experience a number of cycles larger than 10 million cycles. For that reason, the region of very high cycle fatigue (VHCF), and the concept of fatigue limit has been matter of study and interest in the last decades. In order to overcome the ti e e ff ort required, ultrasonic fatigue testing machine has being developed and widely used. Nevertheless, ultrasonic testing system and the VHCF region brought new challenges such as the frequency e ff ect and the internal crack initiation. Thus, this research work intends to characterize the fatigue behaviour of S690 structural steel in the VHCF region. An experimental campaign of twenty specimens was performed in ultrasonic testing machine at a frequency of 20 kHz and a mean curve was determined. This work also approaches a design methodology of smooth fatigue specimens to be tested in ultrasonic fatigue machine. © 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: Very high cycle fatigue; Structural steel; Ultrasonic testing Abstract Testing beyond 10 millions of cycles in a conventional fatigue machine is a very time consuming task, so the fatigue limit has been settled around this number of cycles. However, during the service life, several engineering components experience a number of cycles larger than 10 million cycles. For that reason, the region of very high cycle fatigue (VHCF), and the concept of fatigue limit has been matter of study and interest in the last decades. In order to overcome the time e ff ort required, ultrasonic fatigue testing machine has being developed and widely used. Nevertheless, ultrasonic testing system and the VHCF region brought new challenges such as the frequency e ff ect and the internal crack initiation. Thus, this research work intends to characterize the fatigue behaviour of S690 structural steel in the VHCF region. An experimental campaign of twenty specimens was performed in ultrasonic testing machine at a frequency of 20 kHz and a mean curve was determined. This work also approaches a design methodology of smooth fatigue specimens to be tested in ultrasonic fatigue machine. 23 European Conference on Fracture – ECF23 Very high cycle fatigue behaviour of S690 structural steel Rita Dantas a,b,c, ∗ , Michael Gouveia a,b , Filipe G.A. Silva b , Felipe Fiorentin a,b , Ab´ılio de 23 European Conference on Fracture – ECF23 Very high cycle fatigue behaviour of S690 structural steel Rita Dantas a,b,c, ∗ , Michael Gouveia a,b , Filipe G.A. Silva b , Felipe Fiorentin a,b , Ab´ılio de b INEGI, Department of Mechanical Engineering, University of Porto, Portugal c CONSTRUCT, Department of Civil Engineering, University of Porto, Portugal d Department of Mechanics, Materials Science and Biomedical Engineering, Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, ul. Smoluchowskiego 25, PL-50370 Wrocław, Poland b INEGI, Department of Mechanical Engineering, University of Porto, Portugal c CONSTRUCT, Department of Civil Engineering, University of Porto, Portugal d Department of Mechanics, Materials Science and Biomedical Engineering, Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, ul. Smoluchowskiego 25, PL-50370 Wrocław, Poland Jesus a,b , Jose´ Correia a,b,c , Grzegorz Lesiuk d a University of Porto, Rua Dr. Roberto Fria, 4200-465 Porto , Portugal Jesus a,b , Jose´ Correia a,b,c , Grzegorz Lesiuk d a University of Porto, Rua Dr. Roberto Fria, 4200-465 Porto , Portugal

1. Introduction 1. Introduction

During the last century, the main focus of fatigue research was low cycle fatigue - usually defined as the region between 10 4 and 10 5 cycles - and high cycle fatigue - the region between 10 5 and 10 7 cycles - while, for certain materials such as steel, the conventional fatigue limit has been settled around 10 7 cycles. The definition of this limit was strongly influenced by cost and time limitations, since testing beyond 10 7 cycles in a conventional machine, which usually works at a maximum frequency of around 50 Hz, would be extremely time consuming (Ilie et al., 2020) (Berger et al., 2008). However, several engineering components and structures can experience a number of cycles larger than During the last century, the main focus of fatigue research was low cycle fatigue - usually defined as the region between 10 4 and 10 5 cycles - and high cycle fatigue - the region between 10 5 and 10 7 cycles - while, for certain materials such as steel, the conventional fatigue limit has been settled around 10 7 cycles. The definition of this limit was strongly influenced by cost and time limitations, since testing beyond 10 7 cycles in a conventional machine, which usually works at a maximum frequency of around 50 Hz, would be extremely time consuming (Ilie et al., 2020) (Berger et al., 2008). However, several engineering components and structures can experience a number of cycles larger than

∗ Corresponding author. Tel.: + 351 22 508 1400; fax: + 351 22 508 14 40 E-mail address: rdantas@inegi.up.pt ∗ Corresponding author. Tel.: + 351 22 508 1400; fax: + 351 22 508 14 40 E-mail address: rdantas@inegi.up.pt

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.2022.12.211 2210-7843 © 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 . 2210-7843 © 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 .