Numerical Stress Analysis during Cooldown and Compressive Loading in an Imperfect Nb3Sn Wire

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.