Finite Element Analysis of Magnetoelastic Buckling of Eight-Coil Superconducting Full Torus

Abstract

A method of numerical analysis of the magnetoelastic buckling of toroidal field coils is shown on the basis of finite element method. Lagrange’s equation is used to deduce an eigenvalue equation determining the buckling current of the toroidal coils. The Lagrangian consists of elastic strain energy and magnetic energy. Since the coil is unidirectional, fiber-reinforced composite material, the theory of orthotropy is applied to determine elastic constants at 4.2 K. A buckling experiment on the eight superconducting-coil full torus was conducted to verify the numerical method developed here. A comparison of the numerical results with the experimental result is fairly good.