PSI - Issue 33

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

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www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 33 (2021) 1055–1064

© 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 Abstract Spherical pressure vessels are widely used in various industrial processes, for storage and transportation of compressed gases, liquids and other substances. Since most pressure vessels are made of metals, they are often prone to pitting corrosion. To assess and ensure long-term reliability and strength of the structure, it is necessary to analyse stresses concentrated in the vicinity of defects. The present paper focuses on the effect of interaction of neighbouring defects on the stress state of the pressure vessel. А spherical shell with multiple surface defects, under internal pressure is considered. The defects are assumed to have a shape of nearly hemispherical notches of equal sizes with the depth equal to half of its curvature radius. Different numbers of notches with their random arrangement along the equator of the shell are considered. The stress state of the shell is analysed by finite element method using the ANSYS Workbench package. Calculations are made within the frame-work of bilinear plasticity hardening model and linearly elastic model. The effect of the distance between neighbouring defects on the growth of stresses in the vessel for various numbers of random and periodical defects is investigated. The maximum values of stresses were observed in the zones of sharp edges formed between the notches, which slightly overlap or almost touch one another. It is shown that the distance between neighbouring defects is an important but not the only factor affecting the growth of maximum stresses in the pressure vessel weakened by defects. © 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 IGF26 - 26th International Conference on Fracture and Structural Integrity The Effect of Surface Defects Int raction on the Strength of a Pressurised pherical Shell D.D. Okulova a , O.S. Sedova a , Yu.G. Pronina a * a Saint Petersburg State University, St.Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia Abstract Spherical pressure vessels are widely used in various industrial processes, for storage and transportation of compressed gases, liquids and other substances. Since most pressure vessels are made of metals, they are often prone to pitting corrosion. To assess and ensure long-term reliability and strength of the structure, it is necessary to analyse stresses concentrated in the vicinity of defects. The present paper focuses on the effect of interaction of neighbouring defects on the stress state of the pressure vessel. А spherical shell with multiple surface defects, under internal pressure is considered. The defects are assumed to have a shape of nearly hemispherical notches of equal sizes with the depth equal to half of its curvature radius. Different numbers of notches with their random arrangement along the equator of the shell are considered. The stress state of the shell is analysed by finite element method using the ANSYS Workbench package. Calculations are made within the frame-work of bilinear plasticity hardening model and linearly elastic model. The effect of the distance between neighbouring defects on the growth of stresses in the vessel for various numbers of random and periodical defects is investigated. The maximum values of stresses were observed in the zones of sharp edges formed between the notches, which slightly overlap or almost touch one another. It is shown that the distance between neighbouring defects is an important but not the only factor affecting the growth of maximum stresses in the pressure vessel weakened by defects. © 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 IGF26 - 26th International Conference on Fracture and Structural Integrity The Effect of Surface Defects Interaction on the Strength of a Pressurised Spherical Shell D.D. Okulova a , O.S. Sedova a , Yu.G. Pronina a * a Saint Petersburg State University, St.Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia

* Corresponding author. fax: +7-812-428-71-59. E-mail address: y.pronina@spbu.ru

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 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 * Corresponding author. fax: +7-812-428-71-59. E-mail address: y.pronina@spbu.ru

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.2021.10.117