PSI - Issue 59

Ihor Dmytrakh et al. / Procedia Structural Integrity 59 (2024) 74–81 Ihor Dmytrakh et al. / Structural Integrity Procedia 00 (2024) 000 – 000

81

8

Based on the above-considered data, it can be suggested that the presence of the crack-like defects in the pipelines is very dangerous from the point of view of their further reliable operation. This danger significantly increases with the increase of the hydrogen concentration in the metal. Regarding to the defect types for both sizes of pipelines, the increase of the crack-like defects danger in the pipe, may be expressed by the sequence: a longitudinal semi-elliptical crack at outer surface – a longitudinal semi-elliptical crack at inner surface – a circumferential semi-elliptical crack at inner surface (Fig. 8). So, the circumferential semi elliptical crack at the inner surface of pipelines is the most dangerous, especially with the low value of the a / c ratio. 5. Conclusions It has been shown that the presence of the crack-like defects in the pipelines is very dangerous from the point of view of their further reliable operation. This danger significantly increases with the increase of the hydrogen concentration in the metal. The increase of the crack-like defects danger in the pipes may be expressed by the sequence: a longitudinal semi elliptical crack at the outer surface – a longitudinal semi-elliptical crack at the inner surface – a circumferential semi-elliptical crack at the inner surface. The residual durability of defected pipe N f was chosen as the basic parameter for the assessment of its further serviceability. Thus, all defects discovered in the pipeline after inspection can be compared with data, which contain in database and the expert conclusion for the evaluation of each defect potential risk can be made. Acknowledgements This work was financially supported by the National Research Foundation of Ukraine (Project No: 2020.02/0049). References Andreikiv, O.E., Hembara, N.T., 2022a. A mathematical model for the determination of hydrogen concentration corresponding to changes in the mechanism of deformation. Journal of Mathematical Sciences 263, 15 – 24. Andreikiv, O.Y., Hembara, N., 2022b. Modeling of the influence of hydrogen on the deformation of metals. Materials Science 57, 774 – 781. ANSI/NACE SP0502-2010 Pipeline External Corrosion Direct Assessment Methodology, Standard Practice, 2010. Askari, M., Aliofkhazraei, M., Afroukhteh, S., 2019. A comprehensive review on internal corrosion and cracking of oil and gas pipelines. Journal of Natural Gas Science and Engineering 71, 102971. Bolzon, G., Gabetta, G., Nykyforchyn, H., 2021. Degradation assessment and failure prevention of pipeline systems, in “ Lecture Notes in Civil Engineering ”. In: Bolzon, G., Gabetta, G., Nykyforchyn, H. (Eds.). Springer Nature, 102, pp. 252. Cheng, Y.F., 2007. Fundamentals of hydrogen evolution reaction and its implications on near-neutral pH stress corrosion cracking of pipelines. Electrochimica Acta 52, 2661 – 2667. Dmytrakh, I.M., 2011. Corrosion fracture of structural metallic materials: effect of electrochemical conditions in crack. Strain 47, 427 – 435. Dmytrakh, I.M., Leshchak, R.L., Syrotyuk, A.M., 2015. Effect of hydrogen concentration on strain behaviour of pipeline steel. International Journal of Hydrogen Energy 40, 4011 – 4018. Dmytrakh, I .M., Tóth, L., Bilyy, O.L., Syrotyuk, A.M., 2012. Workability of materials and structural elements with sharp -tipped stress concentrators: Vol. 13, in “Fracture mechanics and strength of materials: Reference manual”. In: Panasyuk, V.V. (Editor-in-Chief). Publishing House “SPOLOM”, Lviv, pp. 316. Dmytrakh, І.М., Syrotyuk, A.М., Leshchak, R.L., 2018. Specific features of the deformation and fracture of low -alloy steels in hydrogen containing media: influence of hydrogen concentration in the metal. Materials Science 54, 295 – 308. Dmytrakh, І.М., Syrotyuk, А.М., Leshchak, R.L., 2021. Specific features of electrochemical hydrogenation of low -alloy pipeline steel in a model solution of ground water. Materials Science 57, 276 – 283. Dutkiewicz, M., Hembara, O., Chepil, O., Hrynenko, M., Hembara, T., 2023. A new energy approach to predicting fracture resistance in metals. Materials 16, 1566. Kryzhanivs’kyi, E. І., Hrabovs’kyi, R. S., Vytyaz’, О. Y., 2019. Influence of the geometry of corrosion -fatigue cracks on the residual service life of objects intended for long-term operation. Materials Science 54, 647 – 655. LECO DH603, 2019. Manual, LECO Corporation. Nyrkova, L., 2020. Stress-corrosion cracking of pipe steel under complex influence of factors. Engineering Failure Analysis 116, 104757. Ohaeri, E., Eduok, U., Szpunar, J., 2018. Hydrogen related degradation in pipeline steel: A review. International Journal of Hydrogen Energy 43, 14584 – 14617. Skalskyi, V., Andreikiv, O., Dolinska, I., 2018. Assessment of subcritical crack growth in hydrogen-containing environment by the parameters of acoustic emission signals. International Journal of Hydrogen Energy 43, 5217 – 5224. Suresh, S., 1998. Fatigue of Materials. 2nd edition. Cambridge University Press, Cambridge, pp. 679.

/c=0,25 /c=0,50 /c=0,75

тепенной (a/c=0,25) тепенной (a/c=0,50) тепенной (a/c=0,75)

= 8832,9x -0,9346 R 2 = 0,9985

= 18983x -0,8481 R 2 = 0,9995

= 48086x -0,7516 R 2 = 0,9998