PSI - Issue 42

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ScienceDirect

Procedia Structural Integrity 42 (2022) 1626–1633 Structural Integrity Procedia 00 (2022) 000–000 Structural Integrity Procedia 0 (2022) 000–000

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

© 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 Tensile residual stresses are a byproduct of welding processes with a negative impact on fatigue life and structural integrity. In large welded structures, the residual stress field will be superimposed on the service and structural loads, thus potentiating structural limit conditions. Due to the high manufacturing costs involved and harsh environments in which large length welded joints may operate, it is highly desirable to have an overview of the residual stresses present in the structure.In order to gain further insight on the magnitude and nature of welding residual stresses introduced into tubular steel towers, two specimens that were circumferentially welded were obtained from two towers. The specimens were extracted from door cut-outs that permit access inside the towers. The Contour method was employed for measuring the locked-in residual stress, and in order to characterize the welds, a microstructural analysis was performed, and mechanical properties, such as impact toughness and Vickers hardness, were assessed. 20 2 The Authors. Published by Elsevier B.V. is is an open access article under the CC BY-NC-ND license (http: // creativec mmons.org / licenses / by-nc-nd / 4.0 / ) r-review under responsibility of 23 European Conference on F acture – ECF23 . Keywords: Residual stress; Submerged-arc welding; Wind turbines; 23 European Conference on Fracture – ECF23 Residual stress measurements and weld characterization in wind turbine support structures Mihai A. Popescu a,b , Daniel F.O. Braga a,b , Mario A.P. Vaz a,b , Francisco J.M.Q. Melo a,b a Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, Porto 4200-465 , Portugal b Institute of Mechanical Engineering and Industrial Management (INEGI), Campus da FEUP, Rua Dr. Roberto Frias 400, Porto 4200-465 , Portugal Abstract Tensile residual stresses are a byproduct of welding processes with a negative impact on fatigue life and structural integrity. In large welded structures, the residual stress field will be superimposed on the service and structural loads, thus potentiating structural limit conditions. Due to the high manufacturing costs involved and harsh environments in which large length welded joints may operate, it is highly desirable to have an overview of the residual stresses present in the structure.In order to gain further insight on the magnitude and nature of welding residual stresses introduced into tubular steel towers, two specimens that were circumferentially welded were obtained from two towers. The specimens were extracted from door cut-outs that permit access inside the towers. The Contour method was employed for measuring the locked-in residual stress, and in order to characterize the welds, a microstructural analysis was performed, and mechanical properties, such as impact toughness and Vickers hardness, were assessed. © 2022 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: Residual stress; Submerged-arc welding; Wind turbines; 23 European Conference on Fracture – ECF23 Residual stress measurements and weld characterization in wind turbine support structures Mihai A. Popescu a,b , Daniel F.O. Braga a,b , Mario A.P. Vaz a,b , Francisco J.M.Q. Melo a,b a Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, Porto 4200-465 , Portugal b Institute of Mechanical Engineering and Industrial Management (INEGI), Campus da FEUP, Rua Dr. Roberto Frias 400, Porto 4200-465 , Portugal

1. Introduction 1. Introduction

Wind has played an important part in the history of humankind since the dawn of time, playing an even more im portant role in recent years. This is undoubtedly due to e ff ects of fossil fuels on climate change, and an ever-increasing demand for energy. Harvesting wind power to produce electrical energy has proved to be a viable alternative. Reducing costs, while maintaining quality standards for high-performance engineering structures, requires the careful planning of the entire production process, taking into account the occurrence of possible manufacturing errors. When errors occur, they derail the entire process and can lead to delays in delivery and an increase in total costs. Wind has played an important part in the history of humankind since the dawn of time, playing an even more im portant role in recent years. This is undoubtedly due to e ff ects of fossil fuels on climate change, and an ever-increasing demand for energy. Harvesting wind power to produce electrical energy has proved to be a viable alternative. Reducing costs, while maintaining quality standards for high-performance engineering structures, requires the careful planning of the entire production process, taking into account the occurrence of possible manufacturing errors. When errors occur, they derail the entire process and can lead to delays in delivery and an increase in total costs.

∗ Corresponding author. E-mail address: mihaipopescu@fe.up.pt (Mihai A. Popescu) ∗ Corresponding author. E-mail address: mihaipopescu@fe.up.pt (Mihai A. Popescu)

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.2022.12.205 2210-7843 © 2022 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 u der responsibility of 23 European Conference on Fracture – ECF23 . 2210-7843 © 2022 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 .