PSI - Issue 40

Vladlen Nazarov et al. / Procedia Structural Integrity 40 (2022) 334–340 Vladlen Nazarov / Structural Integrity Procedia 00 (2022) 000 – 000

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The numeric value of the material parameter  determines the effect of each of the maximum stresses max  and max 2  on the rupture time. Nazarov et al. (2020) had been shown that the equivalent stress (13) allows better description of the creep rupture process than the equivalent stress (11) under simultaneous tension and compression of an elementary plane element, when the tubular specimen is subjected to the simultaneous action of torque and axial force. 4. Conclusion To approximate the experimental dependences of the strain rate on the nominal stress and the rupture time on the nominal stress, it is better to use a dependences (3) and (4) with four material parameters. The difference between the total errors for the two approximations depends on the specific experimental data. For some experimental data, this difference is significant, for others it is insignificant. To describe the process of secondary creep when a tubular specimen is subjected to the simultaneous action of a torque and an axial force, dependence (7) should be used. To approximate the experimental data on creep rupture obtained under simultaneous internal pressure and tension of tubular specimens, it is better to use as an equivalent stress (11). To approximate the experimental data on creep rupture obtained under simultaneous torsion and tension of tubular specimens, it is better to use as an equivalent stress (13). Acknowledgements This work was partia lly supported by the Russian Foundation for Basic Research (grant 20−08−00387). References Andrade, E., 1910. On the Viscous Flow in Metals and Allied Phenomena. Proceedings of the Royal Society, London 84(567), pp. 1−12. Bailey, R., 1029. Creep of Steel under Simple and Compound Stresses and the Use of High Initial Temperature in Steam Power Plant. Transactions of the World Power Conference, Tokyo 3. Himeno, T., Chuman, Y., Tokiyoshi, T., Fukahori, T., Igari, T., 2016. Creep Rupture Behaviour of Circumferentially Welded Mod. 9Cr – 1Mo Steel Pipe Subject to Internal Pressure and Axial Load. Materials at High Temperatures 33(6), 636−643. Kobayashi, H., Ohki, R., Itoh, T., Sakane M., 2017. Multiaxial Creep Damage and Lifetime Evaluation under Biaxial and Triaxial Stresses for Type 304 Stainless Steel. Engineering Fracture Mechanics 174, 30−43. Lasdon, L., Fox, R., Ratner, M., 1974. Nonlinear Optimization using the Generalized Reduced Gradient Method. Operations Research 8(V3), 73−103. Lebedev, A., 1996. The Theory of Equivalent Stresses as a Problem of Mechanics of Materials . Strength of Materials 28(2), 94−108 . Lokoshchenko, A., Shesterikov A., 1986. Investigation of the Creep Rupture of Metals under Complex Stress State. Problems of Strength 12, 3−8. Lokoshchenko, A., Nazarov, V., 2004. The Choice of the Creep Rupture Criteria of Metals under Complex Stress. Aviation and Space Technology 7(15), 124−128. Lokoshchenko, A., Nazarov, V., 2005. Kinetic Approach to the Study of the Creep Rupture of Metals under Biaxial Tension. Aviation and Space Technology 10(26), 73−79. Lokoshchenko, A., Nazarov, V., 2009. Long Term Strength of Metals under an Equiaxial Plane Stress State. Journal of Applied Mechanics and Technical Physics 50(4), 670 – 676. Nazarov, V., 2014. Determination of Creep Properties under Tension and Torsion of Copper Tubular Specimens. Inorganic Materials 50, 1514−1515. Nazarov, V., 2015. Description of Steady State Creep during Tension and Torsion of Tubular Specimens. Industrial Laboratory. Diagnostics of Materials 81(7), 60−61. Nazarov, V., Lepeshkin, A., 2017. A Method for Calculating Creep Limits. Diagnostics, Resource and Mechanics of Materials and Structures 1, 36 – 42. Nazarov, V., 2019. Analysis of Two Methods for Calculating the Ultimate Stresses of Creep and Creep Rupture Processes. Diagnostics, Resource and Mechanics of Materials and Structures 2, 28 – 36. Nazarov, V., Lepeshkin, A., 2020. Analysis of Various Equivalent Stress Options for Describing the Creep Rupture Process under a Complex Stress State. AIP Conference Proceedings 2315, 020029.