PSI - Issue 16

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

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ScienceDirect

Procedia Structural Integrity 16 (2019) 148–152

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers. © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers Th calculation model is eveloped to evaluate the residu l lif time of a pipe with a crack considering in-service egradation of the pipeline steel and the effect of soil corrosion. The m del is base on the first law of therm dynamics. The proble determination of the p riod of subcritical crack growth in a pip is reduced to the differential equation subjected to definite initial and final conditions. Obtained equati n together with the boundary conditions are us d for predictio of the r sidual lifetime of the pipe made of the X52 pipe ste l. The pipe contains external surface semi-elliptical crack. The task consists in t determination of the time of crack propagation through the pipe wall till its decompression. According to the experimental data, cracks in the studied steel under long-term loading and soil corrosion propagate mainly at constant rat , which is diff rent for the as-received pipeline st el and the steel after 30 years in service. Based on the e data, the equation for ap roximate d termination of the crack growth rate for arbitrar service time of the pipe made of the X52 steel is proposed. To evaluate the crack propagation time, the energy approach is employed. F r a crack that r mains semi-elliptical during propagation, the probl m is reduced to the ifferential equation syste that determines the variations of the crack s mi-ax s. The system solution under definite initial and final conditions renders the expression for the pipe residual lifetime. The dependences of pipe residual lifetime on initial crack depth and pipe operation time are derived. The strong influence of the time of steel previous service on the pipe residual lif time is manifested. © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” Prediction of the residual lifetime of gas pipelines considering the effect of soil corrosion and material degradation Ivan Shtoyko a *, Jesús Toribio b , Viktor Kharin b , Myroslava Hredil a a Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, 5, Naukova St., Lviv 79060, Ukraine; b Fracture & Structural Integrity Research Group (FSIRG), University of Salamanca (USAL), E.P.S., Campus Viriato, 49022 Zamora, Spain. The calculation model is developed to evaluate the residual lifetime of a pipe with a crack considering in-service degradation of the pipeline steel and the effect of soil corrosion. The model is based on the first law of thermodynamics. The problem of determination of the period of subcritical crack growth in a pipe is reduced to the differential equation subjected to definite initial and final conditions. Obtained equation together with the boundary conditions are used for prediction of the residual lifetime of the pipe made of the X52 pipe steel. The pipe contains external surface semi-elliptical crack. The task consists in the determination of the time of crack propagation through the pipe wall till its decompression. According to the experimental data, cracks in the studied steel under long-term loading and soil corrosion propagate mainly at constant rate, which is different for the as-received pipeline steel and the steel after 30 years in service. Based on these data, the equation for approximate determination of the crack growth rate for arbitrary service time of the pipe made of the X52 steel is proposed. To evaluate the crack propagation time, the energy approach is employed. For a crack that remains semi-elliptical during propagation, the problem is reduced to the differential equation system that determines the variations of the crack semi-axes. The system solution under definite initial and final conditions renders the expression for the pipe residual lifetime. The dependences of pipe residual lifetime on initial crack depth and pipe operation time are derived. The strong influence of the time of steel previous service on the pipe residual lifetime is manifested. 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” Prediction of he res dual lifetime of g s p pelines considering the effect of soil corrosion and material degradation Ivan Shtoyko a *, Jesús Toribio b , Viktor Kharin b , Myroslava Hredil a a Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, 5, Naukova St., Lviv 79060, Ukraine; b Fracture & Structural Integrity Research Group (FSIRG), University of Salamanca (USAL), E.P.S., Campus Viriato, 49022 Zamora, Spain. Abstra t Abstract Keywords: steel; residual lifetime assessment; pipelines; corrosion; material degradation; energy approach.

Keywords: steel; residual lifetime assessment; pipelines; corrosion; material degradation; energy approach.

* Corresponding author. Tel.: +38-032-263-2133; fax: +38-032-264-9427. E-mail address: ivan.shtoyko@gmail.com

2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers 2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers * Corresponding author. Tel.: +38-032-263-2133; fax: +38-032-264-9427. E-mail address: ivan.shtoyko@gmail.com

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers. 10.1016/j.prostr.2019.07.034