Magneto-Mechanical Coupling Analysis of a Superconducting Solenoid Magnet in Self-Magnetic Field

For high-precision scientific instruments, the accuracy and sensitivity of the magnet system and the quality of field generated strongly depend upon the disturbance of structures. Since the superconducting structural devices with high transport current are often exposed to large Lorentz forces, which lead to the unavoidable deformation inside superconducting coils, the deformation and configuration change will affect the accurate operation of the magnet system and even its stability. For simplicity, the linear theory is commonly utilized for the stress/strain evaluation of the superconducting coils arising from electromagnetic forces. The aim of the present work is to formulate the equations governing the magneto-mechanical characteristics of a superconducting solenoid system. Due to the axisymmetry, 2-D numerical modeling for the superconducting solenoid is performed to calculate the hoop stress/strain and magnetic field. Maxwell's equations and the equilibrium equations for mechanical deformation have been simultaneously solved by means of coupled finite element method. The numerical results have good agreement with the experimental observations and show the magneto-mechanical coupling of the solenoid superconducting magnet in the self-magnetic field is remarkable especially for a high field or large transport current in the coils.