PSI - Issue 18

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

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

ScienceDirect

Procedia Structural Integrity 18 (2019) 622–629

25th International Conference on Fracture and Structural Integrity Assessment of dents for gas pipelines 25th International Conference on Fracture and Structural Integrity Assessment of dents for gas pipelines

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: cylindrical shell; angular misalligment; approximate solution; Keywords: cylindrical shell; angular misalligment; approximate solution; Yaroslav Dubyk a *, Iryna Seliverstova b a IPP-Centre LLC, 8 Bolsunovska str, Kyiv, 01014, Ukraine b G.S. Pysarenko Institute for Problem of Strength, National Academy of Sciences of Ukraine, 2 Tymiriazevska str, Kyiv, 01014, Ukraine Abstract The analytical solution of the stress-strain state for pipe with dent based on the method of equivalent loads is developed. The shape of the dent is given in an analytic smooth function for which a semi-analytical solution is found. As a basic, a harmonic dent is considered, the displacements of which are easily calculated, therefore, forces and moments can be easily found. A solution for a single dent is obtained based on expansion in Fourier series. A comparison of analytical and numerical results for the axial force and pressure load is given. Influence of the dent profile to stress concentration factor is discussed. Yaroslav Dubyk a *, Iryna Seliverstova b a IPP-Centre LLC, 8 Bolsunovska str, Kyiv, 01014, Ukraine b G.S. Pysarenko Institute for Problem of Strength, National Academy of Sciences of Ukraine, 2 Tymiriazevska str, Kyiv, 01014, Ukraine Abstract The analytical solutio of the stress-strain state for pipe ith dent based on the method f equivalent loads is developed. The shape of the dent is given in an a alytic smooth function for which a s mi-analytical solution is fou d. As a basic, a harmonic dent is considered, the displacements of which are easily calculat d, therefore, f rces d moments can b easily found. A solution for a single dent is btained based on expansion in Fourier series. A comparison of analytical and numerical results for the axial force and pressure load is given. Influence of the dent profile to stress concentration factor is discussed. 1. Introduction Trunk pipelines are one of the most common means used in the transportation of various kinds of energy resources. Ensuring trouble-free operation of pipelines, of course, is a pledge of both the environmental and energy security of the country through which they pass. The most common cause of accidents on trunk pipelines is the presence of mechanical damage (dents and gauges) and corrosion (EGIG, 2015). Therefore, the key point in the study of the technical condition and the extension of the life of trunk pipelines is the determination of their stress state, taking into account these local damages. Dents are one of the most common types of defects arising due to external interaction – damage by heavy machinery (excavators, tractors, pipe layers), falling stones on top of a pipeline or resting on supports (Kec and Cerny, 2017). The mechanics of a dented pipeline are quite complicated. To assess this problem all phases of the dent life cycle we have to consider contact mechanics and nonlinearities in both material and geometry. Recently these problems are 1. Introduction Trunk pipelines are one of the most common means used in the transportation of various kinds of energy resources. Ensuring trouble-free operation of pipelines, of course, is a pledge of both the environmental and energy security of the country through which they pass. The most common cause of accidents on trunk pipelines is the presence of mechanical damage (dents and gauges) and corrosion (EGIG, 2015). Therefore, the key point in the study of the technical condition and the extension of the life of trunk pipelines is the determination of their stress state, taking into account these local damages. Dents are one of the most common types of defects arising due to external interaction – damage by heavy machinery (excavators, tractors, pipe layers), falling stones on top of a pipeline or resting on supports (Kec and Cerny, 2017). The mechanics of a dented pipeline are quite complicated. To assess this problem all phases of the dent life cycle we have to consider contact mechanics and nonlinearities in both material and geometry. Recently these problems are

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. * Corresponding author. Tel.: +38-050-990-1227. E-mail address: dubykir@gmail.com * Corresponding author. Tel.: +38-050-990-1227. E-mail address: dubykir@gmail.com

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.208