Preliminary Mechanical Analysis of Nb3Sn Rutherford Conductor

Abstract

Development of a 14T MRI magnet with a 900 mm warm bore was initiated by the Hefei Institute of Physical Science, Chinese Academy of Sciences. The homogeneity of the MRI magnet is less than 0.5 ppm in the spherical space with 22 cm diameter. A type of conductor like 11.7 T MRI Magnet is developed, which is called Rutherford cable in Channel (RIC). RIC conductor is subjected to huge electromagnetic loads and mechanical load during the operational period. Excessive strain occurred in Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn cable will lead to degradation of cable performance. This paper is focusing on the conductor mechanical analysis of the 14 T MRI magnet systems. Firstly, a `unit cell' finite element (FE) model of the channel and insulation is built based on the conductor we designed. Then the equivalent material properties used for 14 T MRI main magnet are calculated according to the generalized Hooke's law. Finally, a quarter FE model is created based on the structural design of magnet system with the preload structure to investigate the stress and strain of conductor under the different operating conditions.