Journal of Mathematical Sciences

, Volume 162, Issue 2, pp 161–179

# Diagnostics of residual stresses and estimation of their influence on the static strength of welded joints of pipes with different thicknesses with crack-type defects

• Yu. V. Porokhovs’kyi
• O. O. Ivanchuk
Article

Within the framework of the calculation-experimental method suggested by Pidstryhach and his followers, a athematical model for definition of residual stresses in the zone of circular welded joints of pipes with different thicknesses is developed. We constructed a functional to determine the residual thermoplastic strains on the basis of theoretical relations and experimental data obtained by a nondestructive (semidestructive) methods. Using the two-parametric criterion R6 of fracture mechanics and a failure assessment diagram constructed on its basis, the strength reserve coefficients of a welded joint of the main pipeline with different thicknesses under internal pressure and the presence of a surface crack in the thinner pipe wall are determined. The influence of residual stresses on the strength reserve coefficients is estimated.

## Keywords

Welding Residual Stress Weld Joint Stress Intensity Factor Static Strength
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

## References

1. 1.
V. L. Berezin and A. F. Suvorov, Welding of Pipelines and Structures [in Russian], Nedra, Moscow (1983).Google Scholar
2. 2.
V. A. Vinokurov and A. G. Grogoryants, Theory of Welding Strains and Stresses [in Russian], Mashinostroenie, Moscow (1984).Google Scholar
3. 3.
V. A. Dragilev and V. A. Osadchuk, “A mathematical model for the calculation-experimental determination of residual stresses in main pipelines near assembling welds,” Rozv. Rozr. Naft. Gaz. Rod., No. 1(14), 24–29 (2005).Google Scholar
4. 4.
O. O. Ivanchuk and V. A. Osadchuk, “A mathematical model for the calculation-experimental diagnostics of a stress state of circular welded joints of pipes with different thicknesses in main pipelines,” Metod. Pryl. Kont. Yak., No. 5, 97–100 (2005).Google Scholar
5. 5.
V. I. Kyr’yan, V. A. Osadchuk, and M. M. Nykolyshyn, Fracture Mechanics of Welded Joints of Metallic Structures [in Ukrainian], SPOLOM, Lviv (2007).Google Scholar
6. 6.
A. A. Dubov, E. A. Demin, A. I. Minaev, and O. I. Steklov, “Control over a stress-strain state of gas pipelines,” Gaz. Prom., No. 2, 58–61 (2002).Google Scholar
7. 7.
V. I. Makhnenko, Numerical Methods of Studying the Kinetics of Welding Stresses and Strains [in Russian], Naukova Dumka, Kiev (1976).Google Scholar
8. 8.
V. I. Makhnenko, “Improvement of the methods of estimation of the residual service life of welded joints of structures under longterm operation,” in: Collection of Main Publications of Employees of the Department of Mathematical Methods of Study of Physical-Chemical Processes in Welding and Special Electrometallurgy of E. O. Paton Institute of Electric Welding of the Ukrainian Academy of Sciences [in Russian], E. O. Paton Institute of Electric Welding, Kiev (2004), pp. 3–12.Google Scholar
9. 9.
V. I. Makhnenko, Service Life of the Safety Operation of Welded Joints and Units of Modern Structures [in Russian], Naukova Dumka, Kiev (2006).Google Scholar
10. 10.
L. M. Lobanov, V. A. Pivtorak, V. V. Savitskii, and G. I. Tkachuk, “A method of determination of residual stresses in welded joints and elements of structures with the use of speckle-interferometry,” Avtom. Svar., No. 1, 25–30 (2006).Google Scholar
11. 11.
A. Ya. Nedoseka, Foundations of Calculations and Diagnostics of Welded Joints [in Russian], IND PROM, Kiev (1998).Google Scholar
12. 12.
V. A. Osadchuk, “The diagnostics of residual technological stresses in elements of structures by the numerical-experimental method,” Mat. Met. Fiz.-Mekh. Polya, 46, No. 1, 88–104 (2003).
13. 13.
V. A. Osadchuk, Yu. V. Banakhevich, and O. O. Ivanchuk, “Determination of the stress state of main pipelines in the zone of circular welds, Fiz.-Khim. Mekh. Mat., 42, No. 2, 99–104 (2006).Google Scholar
14. 14.
Ya. S. Pidstryhach and S. Ya. Yarema, Thermal Stresses in Shells [in Russian], AN Ukr. SSR, Kiev (1961).Google Scholar
15. 15.
Ya. S. Pidstryhach and V. A. Osadchuk, “Study of the stress state of cylindrical shells caused by a given tensor of inconsistent strains and its application to the determination of welding stresses,” Fiz.-Khim. Mekh. Mat., 4, No. 2, 218–224 (1968).Google Scholar
16. 16.
Calculations of the Strength of Operating Main Pipelines with defects. VBN V.2.3–00018201.04–2000 [in Russian], Gosneftegazprom, Kiev (2000).Google Scholar
17. 17.
V. N. Shimanovskii, E. F. Garf, V. A. Permyakov, et al., Types of Structures [in Russian], Naukova Dumka, Kiev (1997), Vol. 2; L. M. Lobanov (Ed.), Welded Building Structures, Vols. 1–3.Google Scholar
18. 18.
B. S. Kasatkin, A. B. Kudrin, L. M. Lobanov, et al., Experimental Methods of Study of Strains and Stresses: Reference Book [in Russian], Naukova Dumka, Kiev (1981).Google Scholar
19. 19.
Fitness-for-Service. American Petroleum Institute. Recommended Practice 579 (2000).Google Scholar
20. 20.
R. P. Harrison, K. Loosemore, J. Milne, and A. R. Dowling, Assessment of the Integrity of Structures Containing Defects, CEGB R6 (1980).Google Scholar
21. 21.
J. Milne, “Failure assessment diagrams and estimates: A comparison for ferritic and austenitic steels,” Int. J. Press. Vess. Piping, 13, 107–125 (1983).

## Authors and Affiliations

• 1
• Yu. V. Porokhovs’kyi
• 1
• O. O. Ivanchuk
• 1
1. 1.“L’vivs’ka Politekhnika” National UniversityLvivUkraine