Influence of material thickness on the ductile fracture of steel plates for shipbuilding

• Autorzy: Jakub Kowalski , Janusz Kozak

Identyfikatory

DOI

10.2478/pomr-2022-0036

• Języki publikacji: EN

Abstrakty

EN

In the shipbuilding industry, the risk of brittle fractures is relatively high because some units operate in arctic or subarctic zones and use high thickness (up to 100 mm) steel plates in their structures. This risk is limited by employing certified materials with a specific impact strength, determined using the Charpy method (for a given design temperature) and by exercising control over the welding processes (technology qualification, production supervision, and non-destructive tests). However, for offshore constructions, such requirements may prove insufficient. For this reason, regulations employed in constructing offshore structures require conducting crack tip opening displacement (CTOD) tests for steel and welded joints with thicknesses exceeding 40 mm for high tensile strength steel and 50 mm for other steel types. Since classification codes do not accept the results of CTOD tests conducted on specimens of sub-sized dimensions, the problem of theoretically modelling the steel construction destruction process is of key importance, as laboratory tests for notched elements of considerable thickness (100 mm and higher) are costly and problems stemming from high loads and a wide range of recorded parameters are not uncommon. The aim of this research is to find a relationship between material thickness and CTOD value, by establishing and verifying a numerical model that allows recalculating a result obtained on a sub-size specimen to a full- size specimen for a ductile fracture mode. This work presents results and conclusions from numerical modelling and compares them with laboratory test results of the elastic-plastic properties of high thickness steel, typically used in offshore applications.

Słowa kluczowe

EN

ductility; toughness; plasticity; CTOD

• Wydawca: Gdańsk University of Technology, Faculty of Ocean Engineering & Ship Technology
• Czasopismo: Polish Maritime Research
• Rocznik: 2022
• Tom: nr 3
• Strony: 160--166
• Opis fizyczny: Bibliogr. 21 poz., rys., tab.

Twórcy

autor

Jakub Kowalski

• Gdańsk University of Technology Narutowicza 11/12 80-233 Gdańsk Poland

• https://orcid.org/0000-0001-9603-1220

autor

Janusz Kozak

• Gdańsk University of Technology Institute of Naval Architecture and Ocean Engineering Narutowicza 11/12 80-233 Gdańsk Poland

• https://orcid.org/0000-0002-0169-5356

Bibliografia

• 1. A. Griffith, ‘The phenomena of rupture and flow in solids’, Philosophical Transactions, vol. 221, pp. 163–198, 1920.
• 2. A. Wells, ‘Application of fracture mechanics at and beyond general yield, Report No. M13/63’, British Welding Journal, pp. 563–590, 1963.
• 3. J. R. Rice, ‘A Path Independent Integral and the Approximate Analysis of Strain Concentration by Notches and Cracks’, J Appl Mech, vol. 35, no. 2, pp. 379–386, Jun. 1968, doi: 10.1115/1.3601206.
• 4. W. Dahl and P. Langenberg, ‘Fracture Toughness of Metallic Materials’, in Encyclopaedia of Materials: Science and Technology (Second Edition), 2001, pp. 3336–3340.
• 5. DNV, RULES FOR CLASSIFICATION, Ships, Part 2 Materials and welding, Chapter 1 General requirements for materials and fabrication. DNV AS, 2022.
• 6. Standards Norway, NORSOK STANDARD M-101, Structural steel fabrication, 5th ed. Lysaker, 2011.
• 7. DNV, DNV OFFSHORE STANDARDS, DNV-OS-B101, Metallic materials. DNV AV, 2021. [Online]. Available: https://rules.dnv.com/docs/pdf/DNV/OS/2021-07/DNV-OS-B101.pdf.
• 8. Polski Rejestr Statków, Rules For Classification and Construction on sea-going ships, Part IX, Materials and Welding. Gdańsk: PRS, 2021. [Online]. Available: https:// www.prs.pl/uploads/mor_p9.pdf.
• 9. BSI, BS 7448-1:1991 - Fracture mechanics toughness tests. Method for determination of KIc, critical CTOD and critical J values of metallic materials. London: BSI, 1991.
• 10. ASTM International, ‘ASTM E1820 - 18a Standard Test Method for Measurement of Fracture Toughness’, 2018.
• 11. ISO, ISO 12135:2016 Metallic materials — Unified method of test for the determination of quasistatic fracture toughness. Geneva, 2016.
• 12. P. L. Moore and A. M. Crintea, ‘Single edge notched tension (SENT) testing at low temperatures’, Proceedings of the Biennial International Pipeline Conference, IPC, vol. 3, 2016, doi: 10.1115/IPC201664021.
• 13. A. Neimitz, Mechanika Pękania. Warszawa: Wydawnictwo Naukowe PWN, 1998.
• 14. T. Kawabata, T. Tagawa, T. Sakimoto, Y. Kayamori, M. Ohata, Y. Yamashita, E. Tamura, H. Yoshinari, S. Aihara, F. Minami, H. Mimura, Y. Hagihara, ‘Proposal for a new CTOD calculation formula’, Eng Fract Mech, vol. 159, pp. 16–34, 2016, doi: 10.1016/j.engfracmech.2016.03.019.
• 15. W. L. Khor, ‘A CTOD equation based on the rigid rotational factor with the consideration of crack tip blunting due to strain hardening for SEN(B)’, Fatigue Fract Eng Mater Struct, vol. 42, no. 7, pp. 1622–1630, Jul. 2019, doi: 10.1111/ffe.13005.
• 16. F. C. Campbell, ‘Fatigue and Fracture: Understanding the Basics’. 2012.
• 17. J. Morrison and J. P. Gough, ‘Specimen size and orientation effects on the toughness of steel weldments’, Journal of Engineering Materials and Technology, Transactions of the ASME, vol. 111, no. 3, pp. 270–277, 1989, doi: 10.1115/1.3226466.
• 18. M. Palombo, S. Sandon, and M. de Marco, ‘An Evaluation of Size Effect in CTOD-SENB Fracture Toughness Tests’, Procedia Eng, vol. 109, pp. 55–64, 2015, doi: 10.1016/j. proeng.2015.06.207.
• 19. J. Kowalski and J. Kozak, ‘The Effect of Notch Depth on CTOD Values in Fracture Tests of Structural Steel Elements’, Polish Maritime Research, vol. 25, no. 2, 2018, doi: 10.2478/ pomr-2018-0058.
• 20. J. Kowalski, ‘Experimental and Numerical Investigation on Specimen Geometry Effect on the CTOD Value for VL-E36 Shipbuilding Steel’, Polish Maritime Research, vol. 28, no. 3, 2021, doi: 10.2478/pomr-2021-0038.
• 21. J. Kowalski and J. Kozak, ‘Numerical Model of Plastic Destruction of Thick Steel Structural Elements’, Polish Maritime Research, vol. 25, no. 2, pp. 78–84, 2018, doi: 10.2478/pomr-2018-0057.

Uwagi

Opracowanie rekordu ze środków MNiSW, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2024).