PSI - Issue 33

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

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

ScienceDirect

Procedia Structural Integrity 33 (2021) 159–170

IGF26 - 26th International Conference on Fracture and Structural Integrity Fatigue of buried dented pipeline specimens Vitor E. L. Paiva a , Giancarlo L. G. Gonzáles a , Ronaldo D. Vieira a , Alexandre S. Ribeiro a , Ana L.F.S. d'Almeida b , José L. F. Freire a, * a PUC-Rio, R. Marquês de São Vicente, 225, 22541-041, Rio de Janeiro, Brazil b CENPES, Petrobras, Av. Horácio Macedo, 950, Rio de Janeiro, Brazil IGF26 - 26th International Conference on Fracture and Structural Integrity Fatigue of buried dented pipeline specimens Vitor E. L. Paiva a , Giancarlo L. G. Gonzáles a , Ronaldo D. Vieira a , Alexandre S. Ribeiro a , Ana L.F.S. d'Almeida b , José L. F. Freire a, * a PU -Rio, R. Marquês de São Vicente, 225, 22541-041, Rio de Janeiro, Brazil b CENPES, Petrobras, Av. Horácio Macedo, 950, Rio de Janeiro, Brazil

© 2021 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 IGF ExCo © 2021 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 Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo s that were buried and subjected to cyclic internal pressur . Hot-spot cyclic strain amplitudes were measured using two experimental t chniques: Digital Image Correlatio (DIC) and Fiber Optic Bragg Strain Gages (FBSG). Fir t, full-field m asurements were taken using DIC identified strain concentration sites that were potential locations or hot-spots for fatigue cracks to initiate. Close to these point-locations, m asurements of strains using FBSG w re also taken, and th results wer then compared with t e DIC results. These fiber gages were also used during the cyclic pressure loading process whil th sp cimens were b ied, in such a way as to monitor any po sible infl nce that might be caused by soil coverture restricting the free deformation occurring in the d nted a e s. Thes cyclic strain values were used to demonstrate hat a simple uniaxial Coffin-Mans n fatigue equation that us s he universal exponents proposed by Manson and the circ mferential strain amplitude n be us d to predict the life of the dent d specimens. Moreover, it was determined that the measured strains at the hot-spot locations were not influenced by the soil coverture. © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https:// reativecommons.org/licenses/by-nc-nd/4.0) Peer-review Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo Abstract This paper reports the results of fatigue tests performed on dented steel pipeline specimens that were buried and subjected to cyclic internal pressure. Hot-spot cyclic strain amplitudes were measured using two experimental techniques: Digital Image Correlation (DIC) and Fiber Optic Bragg Strain Gages (FBSG). First, full-field measurements were taken using DIC identified strain concentration sites that were potential locations or hot-spots for fatigue cracks to initiate. Close to these point-locations, measurements of strains using FBSG were also taken, and the results were then compared with the DIC results. These fiber gages were also used during the cyclic pressure loading process while the specimens were buried, in such a way as to monitor any possible influence that might be caused by soil coverture restricting the free deformation occurring in the dented areas. These cyclic strain values were used to demonstrate that a simple uniaxial Coffin-Manson fatigue equation that uses the universal exponents proposed by Manson and the circumferential strain amplitude can be used to predict the life of the dented specimens. Moreover, it was determined that the measured strains at the hot-spot locations were not influenced by the soil coverture. Abstract This p pe reports the results of fatigue tests performed on d nted steel pipelin s ci

Keywords: Digital Image Correlation; Strain analysis; Buried pipelines; Dents. Keywords: Digital Image Correlation; Strain analysis; Buried pipelines; Dents.

* Corresponding author. Tel.: +55 21 3527-1178. E-mail address: jlfreire@puc-rio.br * Correspon ing author. Tel.: +55 21 3527-1178. E-mail address: jlfreire@puc-rio.br

2452-3216 © 2021 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 Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo 2452-3216 © 2021 The Authors. Published by ELSEVIER B.V. This is an open acc ss article und r the CC BY-NC-ND licens (https:// reativecommons.org/licenses/by-nc-nd/4.0) Peer-review Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo

2452-3216 © 2021 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 IGF ExCo 10.1016/j.prostr.2021.10.020