| A Multiphysics Approach for High Temperature Superconducting Tapes Daniela P. Boso1; 1UNIVERSITY OF PADOVA, Padova, Italy; PAPER: 369/Geomechanics/Keynote (Oral) SCHEDULED: 14:25/Sat. 26 Oct. 2019/Athena (105/Mezz. F) ABSTRACT: Superconductivity is currently exploited in several technological applications, from small-scale electronic devices to large-scale particle accelerators and fusion reactors. High field magnet technologies are still based on the use of low temperature superconducting (LTS) materials, either NbTi or Nb<sub>3</sub>Sn. Nb<sub>3</sub>Sn cables are brittle and strain sensitive [1]-[3], but they perform better than NbTi ones. Actual challenges given by nuclear fusion and high-energy physics require more and more performing materials, capable to transport high current densities at high temperature and at very high magnetic fields [4]. High Temperature Superconducting (HTS) materials are nowadays considered as possible candidates for such demanding conditions. These materials are thus named because they exhibit superconducting behavior at much higher temperatures than NbTi and Nb<sub>3</sub>Sn. Among the various HTS concepts, the coated conductors, also referred to as rare-earth-barium-copper-oxide (Rare-Earth1Ba2Cu3O7-x) or REBCO tapes, are promising competitors. The coated conductor tapes have exhibited high current carrying capability under high magnetic field and good mechanical properties that meet the specific requirements in the superconducting motors and coils [5] – [7]. HTS magnets, however, are a new technology. If the LTS technology is well established, a robust R&D is needed to explore the possible use of high-temperature superconductors in high field magnets, as the superconductors performances are not only influenced by the magnetic field and the operating temperature, but also by the mechanical strain [8]–[9]. As a consequence, the development of these new generations of conductors requires extensive investigation about the impact of the main characteristics of the cable architecture on the electrical performances of a single superconducting tape. In particular, for a proper conductor design, it is important to fully characterize the single tape in its working conditions. In this work, a coupled thermo-electro-mechanical model is developed, suitable to analyze the behavior of HTS tapes and predict their performances inside the coil. The drop of electrical performances at the yield strength of the tapes under different loading conditions is evaluated. The multiphysics model is going to be validated against experimental measurements of the critical current now being performed on REBCO tapes by SuNAM Co., immersed in liquid nitrogen. References: [1] D.P. Boso, A simple and effective approach for thermo-mechanical modelling of composite superconducting wires, Supercond. Sci. Technol., 26, 2013<br />[2] A.S. Nemov, D.P. Boso, I.B. Voynov, A.I. Borovkov, B.A. Schrefler, Generalized stiffness coefficients for ITER superconducting cables, direct FE modeling and initial configuration. Cryogenics, 50, 2010<br />[3] D.P. Boso, M. Lefik, A thermo-mechanical model for Nb3Sn filaments and wires: strain field for different strand layouts, Supercond. Sci. Technol., 22, 2009<br />[4] S.R. Foltyn, l. Civale, J.l. Macmanus-Driscoll, Q. X. Jia, B. Maiorov, H. Wang, M. Maley, Materials science challenges for high-temperature superconducting wire, Nature materials, 6, 2007<br />[5] T. Qu et al., Test of an 8.66-T REBCO insert coil with overbanding radial build for a 1.3-GHz LTS/HTS NMR magnet, IEEE Trans. Appl. Supercond., 27, 2017<br />[6] Y. H. Choi, S. Hahn, J. B. Song, D. G. Yang, and H. G. Lee, Partial insulation of GdBCO single pancake coils for protection-free HTS power applications, Supercond. Sci. Technol., 24, 2011<br />[7] [3] M.Kawamura, J. Jones, Superconducting supermotor and generator, IEEE Trans. Appl. Supercond., 27, 2017.<br />[8] C. Zhou, K. A. Yagotintsev, P. Gao, T. J. Haugan, D. C. van der Laan, and A. Nijhuis, Critical Current of Various REBCO Tapes Under Uniaxial Strain, IEEE Transactions on Applied Superconductivity, 26, 2016<br />[9] N. Bykovsky, D. Uglietti, R. Wesche, P. Bruzzone, Strain Management in HTS High Current Cables, IEEE Transactions on Applied Superconductivity, 25, 2015 |
