PPPL-5375
Numerical Stress Analysis during Cooldown and Compressive Loading
in an Imperfect Nb3Sn Wire
Authors: Y. Zhai
Abstract: High field superconductors are critical to the
success of next step magnetic fusion confinement devices such as
ITER and DEMO. The low-temperature superconducting material that is
currently favored for these applications, Nb3Sn, is susceptible to
performance due to its brittleness and high strain-sensitivity.
Under extreme loads, an irreversible degradation in the maximum
critical current density has been shown to occur and believed to be
strongly influenced by two factors: plasticity and cracked
filaments. Cracks in filaments are induced when sufficiently high
stress concentrations occur in the wire. In this paper, we explore
using finite element analysis the impact that voids have on the
stress distributions and peak stresses under two loading conditions:
transverse compressive loading in a 2D model, and a full cool down
phase in a 3D model.