METHODOLOGICAL BASIS FOR DETERMINING THE DESIGN ICE LOADS ON THE HULL OF MODERN ICE VESSELS IN THE BOW AND STERN AREAS

The hull structure of modern ice vessels has changed significantly compared with the vessels typical at the time of development of the current RMRS Rules. The use of existing approximations for the structure functions as applied to the modern structures of the DAS (double action ships) extremities quite often leads to large discrepancies with direct calculations by the method or by analytical dependencies. Particularly sensitive to the applied formulas are the areas of transition of the bow/stern ends to the cylindrical insert for vessels with vertical sides in the middle part, as well as the very bow/stern sections of the bow/stern areas, where the slopes of the frames and waterlines are maximal.
Upon the analysis of the hull structure features in the bow and stern areas of modern ice vessels including the DAS ones, an original method for constructing dependencies is proposed to determine the parameters of ice loads on the extremities of the vessels having an ice category of the Russian Maritime Register of Shipping. On the basis of the developed methodology, recommendations are made for determining design ice loads on bow and stern areas of double-acting ships further incorporated in the draft requirements of the RMRS Rules for the design of ice hull reinforcement for vessels intended to be operated astern.

1. Platonov V. V., Tryaskin V. N. Arkhitekturno-konstruktivnye osobennosti arkticheskikh sudov dvoinogo deistviya. [Architectural and structural specific features of arctic double action ships]. Arktika: ekolo­giya i ekonomika, 2019, no. 3 (35), pp. 84—96. DOI: 10.25283/2223-4594-2019-3-84-96. (In Russian).

2. Popov Yu. N., Faddeev O. V., Kheisin D. E., Yakovlev A. A. Prochnost’ sudov, plavayushchikh vo l’dakh. [Strength of ships floating in ice]. Leningrad, Sudostroenie, 1967, 224 p. (In Russian).

3. Kurdyumov V. A., Kheisin D. E. Gidrodinamicheskaya model’ udara tverdogo tela o led. [Hydrodynamic Mo­del of Solid Body Impact on Ice]. Prikladnaya mekhanika [Kiev], 1976, pt. 12, iss. 10, pp. 103—109. (In Russian).

4. Kurdyumov V. A., Tryaskin V. N., Kheisin D. E. Opredelenie ledovoi nagruzki i otsenka ledovoi prochnosti korpusov transportnykh sudov. [Determination of Ice Load and Assessment of Ice Strength of Hulls of Transport Vessels]. Ledoprokhodimost’ i ledovaya prochnost’ morskikh sudov. Leningrad, 1979, S. 3—12. (Tr. LKI). (In Russian).

5. Tryaskin V. N., Yakimov V. V. Raschet dopustimykh skorostei dvizheniya sudna vo l’dakh dlya sluchaya naklonnogo borta. Svidetel’stvo o gosudarstvennoi registratsii programmy dlya EVM № 2014618563. [Calculation of permissible speed of the vessel in ice for the case of inclined side. Certificate of state registration of computer programs № 2014618563]. [S. l.], 2014. (In Russian).

6. Pravila klassifikatsii i postroiki morskikh sudov. [Rules for the Classification and Construction of Sea-Going Ships]. Vol. 1. Pt. 2: “Korpus”. Ros. mor. registr sudokhodstva. St. Petersburg, 2019. (In Russian).

7. Pravila klassifikatsii i postroiki morskikh sudov. [Rules for the Classification and Construction of Sea-Going Ships]. Vol. 1. Pt. 2: “Korpus”. Registr SSSR. Leningrad, 1981. (In Russian).

8. Aleksandrov A. V., Platonov V. V., Tryaskin V. N. Razrabotka proekta trebovanii Pravil RMRS k konstruktsii ledovykh usilenii korpusa sudov, prednaznachennykh dlya ekspluatatsii kormoi vpered. [Development of draft RS Rules requirements for hull ice strengthening of ships designed for astern operation]. Nauch.-tekhn. sb. Ros. mor. registra sudokhodstva, 2018, Dec., no. 52/53, pp. 47—56. (In Russian).

9. Tryaskin V. N. Primenenie teorii planirovaniya eksperimenta pri proektirovanii konstruktsii korpusa sudna. [Application of the theory of experiment planning in the design of ship hull structures]. Problemy proektirovaniya korpusnykh konstruktsii: Sb. nauch. tr. LKI. Leningrad, 1987, pp. 26—35. (In Russian).

10. Tryaskin V. N. Metodologiya avtomatizirovannogo proektirovaniya konstruktsii korpusa sudna. [Methodology of computer-aided design of ship hull structures]. Dis. ... d-ra tekhn. nauk. Razd. 3.2. St. Petersburg, 2007. (In Russian).

11. Nalimov V. V., Chernova N. A. Statisticheskie metody planirovaniya ekstremal’nykh eksperimentov. [Statistical methods of planning extreme experiments]. Mocsow, Nauka, 1965, 340 p. (In Russian).

12. Appolonov E. M. Ledovaya prochnost’ sudov, prednaznachennykh dlya kruglogodichnoi arkticheskoi navigatsii. [Ice Strength of Vessels Designed for Year-round Arctic Navigation]. St. Petersburg, Izd-vo SPbGMTU, 2016, 288 p. (In Russian).

13. Appolonov E. M., Nesterov A. B., Sazonov K. E. Reglamentatsiya ekstremal’nykh ledovykh nagruzok na korpusa azimutal’nykh propul’sivnykh sistem sudov ledovogo plavaniya. [Regulation of extreme ice loads on the hull of azimuth propulsion systems of ice navigation vessels]. Tr. TsNII im. akad. A. N. Krylova, 2008, no. 39, pp. 45—68. (In Russian).

14. Kurdyumov V. A., Kheisin D. E. Opredelenie nagruzok pri udare sudna vertikal’nym bortom o kromku ledyanogo polya. [Determination of loads on impact of the vessel vertical side on the edge of the ice field]. Nauch.-tekhn. sb. Registra SSSR, 1984, iss. 14, pp. 3—10. (In Russian).

15. Appolonov E. M., Platonov V. V., Tryaskin V. N. Metodika normirovaniya ledovykh nagruzok na konstruktsii nosovoi okonechnosti sudov s vertikal’nym bortom i bul’bovymi obvodami. [Ice load assignment procedure for bows of ships with vertical sides and bulbous lines]. Tr. Krylov. gos. nauch. tsentra, 2019, special. iss. 1, pp. 17—23. (In Russian).