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On the Mechanical Behavior of a Nb$_3$Sn Superconducting Coil During a Quench: Two-Dimensional Finite Element Analysis of a Quench Heater

New high-field accelerator magnets based on $Nb_3Sn$ superconductors are pushing the boundaries of magnet design and quench protection towards new limits. While their large stored energies and current densities result in a very challenging scenario for magnet protection, their great electromagnetic...

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Detalles Bibliográficos
Autores principales: Ferradas Troitino, J, Ambrosio, G, Bajas, H, Brouwer, L, Ferracin, P, Izquierdo Bermudez, S, Lorenzo Gomez, J V, Mangiarotti, F J, Perez, J C, Ravaioli, E, Tapani Taakala, F, Vallone, G, Senatore, C
Lenguaje:eng
Publicado: 2019
Materias:
Acceso en línea:https://dx.doi.org/10.1016/j.cryogenics.2020.103054
http://cds.cern.ch/record/2712054
Descripción
Sumario:New high-field accelerator magnets based on $Nb_3Sn$ superconductors are pushing the boundaries of magnet design and quench protection towards new limits. While their large stored energies and current densities result in a very challenging scenario for magnet protection, their great electromagnetic forces create also new requirements in terms of magnet design and stress management techniques. Furthermore, the strain sensitivity of $Nb_3Sn$ cables turns the electro-mechanical limits of the conductor into a parameter of the highest importance, where conductor degradation becomes a critical aspect in magnet operation. The coupling of all the above-mentioned considerations during quench is a case of special interest that adds further complexity to the design of $Nb_3Sn$ magnets. The objective of this paper is to provide a complete two-dimensional investigation of the coil and magnet structure mechanics during a quench event. The analysis is performed using a combination of finite element codes that provide the necessary input for the mechanical study. The core of the modelling strategy relies on a thermal-electric model, whose results are directly used as loads in the mechanical simulation. In doing so, the stress evolution during and after a quench is obtained. We focus for this time in the analysis of a quench heater protected magnet, where dynamic effects are of less importance in contrast to other protection systems like CLIQ.