PSI - Issue 17

Tamás Fekete / Procedia Structural Integrity 17 (2019) 464–471

471

Tamás Fekete / Structural Integrity Procedia 00 (2019) 000 – 000

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The assumption that dissipation is universally present is a turning point: if this idea is accepted as correct, then Thermodynamics fundamentally changes the reigning conceptual framework that defines Structural Integrity at the moment. In this sense, introducing modern Thermodynamics as a new background theory for Structural Integrity means a great and essential paradigm shift – in the sense of Kuhn (1984) – in the field. The inevitable introduction of time into the description requires dynamic theories (see Ván and Gróf (2012)). From a mechanical engineering perspective, this means that dynamic material models must be incorporated into the calculation methodologies. Note that in actual materials, structural inhomogeneities (i.e. microstructures) are indeed present. Because of that, at least at finer length scales, nonlocal models need to be introduced (see e.g. Berezovski and Ván (2017), Khantuleva and Shalymov (2017)). Based on further literature studies – not mentioned here – , we expect that in the future, ageing models derived (1) from the Classic Thermodynamics of Irreversible Processes and (2) from more complex, non-local, multi-scale Thermodynamic models will play a complementary role; in industrial assessments, the use of ‘microstructurally informed’, experimentally corrected models are most probably expected. Based on the findings presented sketchily in this paper, it can be stated that modern Thermodynamics is the appropriate background-theory for Structural Integrity ; which also means an essential paradigm shift in the field. Modern Thermodynamics is a holistic theory, interdisciplinary in its nature, wherein time evolution unavoidably enters into the description. It can be argued with great certainty that a generalized methodology for Structural Integrity problems, derived from – or at least clearly rooted in – modern Thermodynamics is a promising approach to build a sound foundation for future – and more accurate – Structural Integrity computations of industrial, large-scale pressure systems, which are expected to have an enhanced predictive power as well. 5. Conclusions ASME 2019, Boiler and Pressure Vessel Code Complete Set, ASME, New York. 2019. Berezovski, A., Ván, P., 2017. Internal Variables in Thermoelasticity. Solid Mechanics and Its Applications 243, Springer International Publishing AG. DOI:10.1007/978-3-319-56934-5_1 Chen, X.H., Mai, Y.W., 2013. Fracture Mechanics of Electromagnetic Materials. Nonlinear Field Theory and Applications. Imperial College Press, London. ESIS, 2019. http://www.structuralintegrity.eu/esis/ accessed 16 April 2019 Fekete, T., 2018. The Prospect of Modern Thermomechanics in Stuctural Integrity Calculations of Large-Scale Pressure Vessels. Continuum Mechanics and Thermodynamics 30 1267 – 1322. https://doi.org/10.1007/s00161-018-0657-3 Hobbs, B.E., Ord, A., Regenauer-Lieb, K., 2011. The thermodynamics of deformed metamorphic rocks: A review. J. Struct. Geol. 33 1 – 61. Kang, K.S., Kupča, L. (eds.), 2010. Pressurized Thermal Shock in Nuclear Power Plants: Good Practices for Assessment, Handbook on Deterministic Evaluation for the Integrity of Reactor Pressure Vessel. IAEA TECDOC-1627, IAEA, Vienna. Khantuleva, T.A., Shalymov, D.S., 2017. Modelling non-equilibrium thermodynamic systems from the speed-gradient principle. Philosophical Transactions R. Soc. A. 375: 20160220. http://dx.doi.org/10.1098/rsta.2016.0220 Kuhn, T., 1984. The Structure of Scientific Revolutions. (in Hungarian) Gondolat Kiadó, Budapest. Martyushev, L.M., 2017. On Interrelation of Time and Entropy. 19 345. doi:10.3390/e19070345 Maugin G.A., 2009. On inhomogeneity, growth, ageing and the dynamics of materials. J. of Mechanics of Materials and Structures. 4:4, 731 – 741 OED 2019, Oxford English Dictionary. Oxford University Press. Oxford. Öttinger, H.C., 2017. A philosophical approach to quantum field theory. Cambridge University Press, Cambridge, New York. PNAE G-7-002-86: Equipment and pipelines strength analysis norms for nuclear power plants. (in Russian) Energoatomizdat, Moscow, 1989. Trampus, P., 2014. Ensuring Safety of Structures and Components at Nuclear Power Plants. Procedia Engineering 86 486 – 495 DOI:10.1016/j.proeng. 2014.11.062 Ván, P., Gróf, Gy., (2012) What is Thermodynamics and what is it good for? Interdisciplinary Description of Complex Systems 10:2 66 – 72. VERLIFE 2013. VERLIFE Guidelines for Integrity and Lifetime Assessment of Components and Piping in VVER Nuclear Power Plants – Version 2013. IAEA, Vienna Acknowledgements This work has been carried out in the frame of VKSZ_14-1-2015-0021 Hungarian project, supported by the National Research, Development and Innovation Fund. References