Fatigue life is one of factors determining the safe service life of tanks under difficult conditions of continuous «drain-fill» operations. The methods of evaluating the fatigue life of tank shell, fixed by the current normative documentation, have several significant drawbacks. At first, the methods don’t consider total actual geometric shape and spatial position of the tank shell, as well as local geometric defects (dents, bulges). Secondly, the methods have differing results of evaluating the fatigue life (the results differ by 1.5 times or more). These drawbacks reduce the reliability of results of evaluating the fatigue life of tank shell and require modernization of the methods in terms of considering the actual shell geometry during calculations.
The joint application of the technology of terrestrial laser scanning and the finite element method will help overcome these drawbacks. The technology of terrestrial laser scanning will be an effective tool for measuring and considering all deviations of the tank shell from the ideal cylindrical shape (including local geometric defects), and the finite element method will be a tool for consider these deviations at evaluating stress-strain state of the tank shell.
The effectiveness of this approach in evaluating the fatigue life of tank shell is demonstrated in this article. The tasks that need to be solved when using the proposed approach at the initial stage are formulated.
1. GOST 31385-2016. Vertical cylindrical steel tanks for oil and oil-products. General specifications, Moscow: Standartinform Publ., 2016, 91 p.
2. STO-0048-2005. Rezervuary vertikal'nye tsilindricheskie stal'nye dlya khraneniya zhidkikh produktov. Pravila proektirovaniya (Vertical cylindrical steel tanks for storage of liquid products. Design rules), Moscow: Publ. of TsNIIPSK, 2005, 88 p.
3. RD 153-112-017-97. Instruktsiya po diagnostike i otsenke ostatochnogo resursa vertikal'nykh stal'nykh rezervuarov (Instructions for the diagnosis and evaluation of the residual life of vertical steel tanks), Ufa: Publ. of USPTU, 1997, 74 p.
4. SA-03-008-08, Rezervuary vertikal'nye stal'nye svarnye dlya nefti i nefteproduktov. Tekhnicheskoe diagnostirovanie i analiz bezopasnosti (metodicheskie ukazaniya) (Vertical steel welded tanks for oil and oil products. Technical diagnostics and safety analysis), Ul'yanovsk: Ul'yanovskiy Dom pechati Publ., 2009, 288 p.
5. RD 08-95-95. Polozhenie o sisteme tekhnicheskogo diagnostirovaniya svarnykh vertikal'nykh tsilindricheskikh rezervuarov dlya nefti i nefteproduktov (Regulations on the system of technical diagnosis of welded vertical cylindrical tanks for oil and oil products), Moscow: Publ of NTTsPB, 2002, 23 p.
6. PNAE G-7-002-89, Normy rascheta na prochnost' oborudovaniya i truboprovodov atomnykh energeticheskikh ustanovok (Norms for calculating the strength of equipment and pipelines of nuclear power plants), Moscow: Energoatomizdat Publ., 1989, 525 p.
7. Vasil'ev G.G., Katanov A.A., Likhovtsev M.V. et al., Work performance on
3-d laser scanning of the vertical stock tank with pontoon (VSTP) 20000 (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2015, no. 1(17), pp. 54-59.
8. Vasil'ev G.G., Katanov A.A., Likhovtsev M.V. et al., Analysis of the three-dimensional laser scanning application on the objects of JSC "Transneft" (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2015, no. 2(18), pp. 48-55.
9. Vasil'ev G.G., Lezhnev M.A., Leonovich I.A., Sal'nikov A.P., Stress-strain state of tanks in operation (In Russ.), Truboprovodnyy transport: teoriya i praktika, 2015, no. 6 (52), pp. 41-44.