Nondestructive Testing of Multilayer HTS Tapes by Using Eddy Current Thermography

This article presents numerical and experimental investigations of the structural control of multilayer high temperature superconducting (HTS) tapes, using eddy current thermography at room temperature. A rotating magnet wheel is used as inductor to avoid the thermal disturbance of current supplied inductors. A 3-D magnetothermal modeling approach based on an integro-differential formulation in terms of the electric vector potential is developed for eddy current computation in the HTS tapes; associated to a thermal modeling using the finite difference method. The source magnetic field is calculated using the magnetic surface charge model. The simulation results are confirmed by the measurements, both highlighting the potential of such control to detect structural defects, such as delamination.