PSI - Issue 28

V. Yu. Filin et al. / Procedia Structural Integrity 28 (2020) 3–10

10 8

Filin V.Yu., Ilyin A.V.,Mizetsky A.V.

/ Procedia Structural Integrity 00 (2020) 000 – 000

5. Discussion Based on FEM simulation results it may be considered that starting from   2.5 the load drop value corresponding to the unstable crack propagation is almost the same for different  but equal  (Fig. 5,a). It means that the cleavage criterion may be related to the load drop (Fig. 5,b), unstable crack extension length and ductile portion in fracture. At the same time the coefficient  may be related to the maximum load and the area below the load-displacement curve, so both values  and  determine the required fracture energy. The main output of the above is that the ductile portion in fracture as a criterion of testing does not completely describe the fracture performance of material but it can be used to assess its ability to arrest a cleavage crack, i.e. TKB and TKDS temperatures correlate with CAT. Simulation results show that the criterion of TKDS temperature is met at   2.8 that corresponds to K I a  41.5 MPa  m 0.5 . A formula by Filin for the expected K I a temperature dependence may be applied, CAT)) ( - exp(0.02 σ /1000 0.44) σ (0.0005 Y(NDT ) Y(NDT ) 1 T S K a   +  = . (12) This way, CAT can be assessed via TKDS, for the above mentioned 40 mm thick steel CAT will be equal to -15°C. Further FEM simulation will be undertaken for materials of other strength levels to find a general TKDS vs. CAT correlation. Acknowledgements This research work is carried out as part of ENI CBC project Energy-efficient systems based on renewable energy for Arctic conditions “EFREA” financed by the European Union, the Russian Federation, and the Republic of Finland, project ID KS1054. The authors are grateful to the Russian Test Laboratory manager Grigory Danilov, one of the authors of TKB test method. References Danilov, G.I. et al. USSR patent No. 1667494. Method of cleavage crack arrest evaluation. – 4674178/28; statement date 13.02.1989; publication date 01.04.1991. Filin, V.Yu., Ilyin, A.V. On the fracture mechanics based development of cleavage fracture resistance criteria for the materials of large-size welded structures. Procedia Structural Integrity 2019, No.14, pp. 758 – 773. Filin, V.Yu. Quality Control of Steels for Large-Sized Welded Structures of the Arctic Shelf: Application of Russian and Foreign Requirements. Inorganic Materials: Applied Research, 2019, Vol. 10, No. 6, pp. 1492 – 1503, doi: https://doi.org/10.1134/S207511331906008X. Hankock, J.W., Mackenzie, A.C. On the mechanisms of ductile failure in high-strength steels subjected to multi-axial stress-states. J. Mech. Phys. Solids, 1976, Vol. 24, pp. 147-169. Ilyin, A.V., Artemiev, D.M., and Filin, V.Yu., Simulation of the propagation and arrest of the brittle fracture in steel plates of different thickness with initial crack using finite element method. Zavodskaya Laboratoria, Diagostika Materialov, 2018, vol. 84, No. 1(I), pp. 56 – 65. McClintock, F.A., J. appl. Mech. 1968, Vol. 35, 363. Rice, J.R., Tracey, D.M. J. Mech. Phys. Solids, 1969, Vol. 17, 201. Shibanuma, K., Yanagimoto, F., Namegawa, T., Suzuki, K., Aihara, S., Brittle crack propagation/arrest behavior in steel plate - Part I: Model formulation, Engineering Fracture Mechanics (2016), doi: http://dx.doi.org/10.1016/j.engfracmech.2016.02.054 Shirahata, H., Okawa, T., Inoue, T., and Ushioda, K. Simplified Evaluation Method for Brittle Crack Arrest Toughness of Steel Plates Exploiting Charpy Impact Test. Tetsu-to-Hagané Vol. 104 (2018) No.3, p.155-165. Ueda, K., Handa, T. Assurance of crack arrestability in EH40-47 steel plates by production test. Technical forum with IACS classification societies, Sep. 17th, 2019. Materialy dl’a sudostroenia i morskoi techniki. Handbook. Chief editor I.V.Gorynin. Saint-Petersburg, NPO Professional, 2009. Vol. 2. ND No. 2-020201-015-E. Rules for the Classification, Construction, and Equipment of Mobile Drilling Units and Offshore Fixed Platforms. Russian Maritime Register of Shipping, Saint-Petersburg, 2018. - 446p.