PSI - Issue 20

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000

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ScienceDirect

Procedia Structural Integrity 20 (2019) 9–16

1st International Conference on Integrity and Lifetime in Extreme Environment (ILEE-2019) Strength of trunk pipelines with critical damages Nikolay A. Makhutov a , Vladimir N.Permyakov b, *, Dmitry O.Reznikov a a Mechanical Engineering Research Institute, RAS. 4 Maly Kharitonievsky lane, Moscow,101990, Russia b Tyumen Industrial University, 47 Respubliki str, Tumen, 625000, Russia Abstract High internal pressure combined with external loading (bending/tension) and aggressive environment, along with the potential presence of local damages makes the assessment of strength and structural integrity of long-distance pipelines a formidable challenge. The paper considers the influence of local buckling (hereafter referred to as crimp) on the reduction of the static strength of pipelines. The reduction of plasticity and the increase of yield limit due to aging; decrease of the operation temperature; residual tensile stresses acting in the inner part of the pipe at the crimp top during plastic crimp formation; and residual tensile stresses caused by welding are assessed. The account of the influence of these damaging factors allows one to evaluate the reduction of the load carrying capacity of damaged pipelines. Threat of occurrence of damages in the form of crimps is either ignored or only partially taken into account by the existing procedures for pipeline strength analysis. The paper is aimed at filling this gap by analyzing strength of pipelines with crimps. Changes of the pipeline geometry, mechanical properties of the material, and stress concentration due to crimp formation are considered; results of calculations and tests are presented. 1st International Conference on Integrity and Lifetime in Extreme Environment (ILEE-2019) Strength of trunk pipelines with critical damages Nikolay A. Makhutov a , Vladimir N.Permyakov b, *, Dmitry O.Reznikov a a Mechanical Engineeri g Re earch I stitute, RAS. 4 Maly Kha itonievsky lane, Moscow,101990, Russia b Tyumen Industrial University, 47 Respubliki str, Tumen, 625000, Russia Abstract High interna pressure combined with ext rnal loading (bending/tension) and aggressive environme t, along with the potential presence of local damage makes the assessment of strength and structural int grity of long-distanc pipelines a ormidable challenge. The pap r consid rs the influence of loc l buckli g (hereafter referred to as crimp) on the reduction of th static strength of pipelines. The reduction of plasticity a d the increase of yield limit due to aging; decrease of the operation t mperature; r sidual tensile stresses acting in the inner part of the pipe at the crimp top during pl stic crimp formation; and residual tensile stresses caused by welding re assesse . Th account of the influen e of these damaging factors allows one to evaluate the re ucti of the load carrying c pacity of damaged pipelines. Threat of occurrenc of dam ge in t form of cr ps is either ignored or only partially taken into account by the existing proc dures for ipeline strength analysis. The paper i aimed at filling this gap by a alyzing strength of pi elines with c imps. Changes of the pipeline geometry, mechanical properties of the material, and stress concentration due to crimp formation are considered; results of calculations and tests are presented.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers Keywords: pipeline; strength; local damage; local buckling; crimp; fracture Keywords: pipeline; strength; local damage; local buckling; crimp; fracture

1. Introduction Ensuring strength and structural integrity of long-distance pipelines (LDP) is one of the critical problems in the process of production, transportation and processing of hydrocarbons. At the end of the 20th and the beginning of the 21st century this problem became critical for ensuring not only of industrial and power engineering safety but 1. Introduction Ensuring strength and structural integrity of long-distance pipeli es (LDP) is one of the critical problems in the process of production, transportation and processing of hydr carbons. At the end of the 20th and the beginning of the 21st century this problem became critical for ensuring not only of industrial and power engineering safety but

* Corresponding author. Tel.: +7-3452-390-343 . E-mail address: v.n.permyakov@mail.ru. * Correspon ing author. Tel.: +7-3452-390-343 . E-mail address: v.n.permyakov@mail.ru.

2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers 2452 3216 © 2019 Th Author(s). Publis d by lsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers 10.1016/j.prostr.2019.12.108