Dependence of the trapped magnetic flux density of YBCO pellets on mechanical stress
Résumé
Most of the latest models of HTS bulk magnetization take into account thermal and electromagnetic behavior but still lack the implementation of the mechanical deformation under strong magnetic fields. The following work tries to fill up partly the gap by proposing a model of the dependence of the electrical conductivity upon mechanical stress during either Zero-Field cooling, Field-cooling or Pulse-Field Magnetizations. This dependence is given by the definition of the critical current density which ultimately defines the amount of magnetic field trapped in the bulk. However, there are no availably published experimental data to depict this dependence. As a first approximation and bearing in mind the obvious discrepancies, it is suggested here to rely on a simple empirical mechanical model inferred from HTS thin films. This first approach allows drawing some generalities on the expected mechanical behavior of cylindrical shaped YBCO pellets during magnetization. The utter goal is to determine design parameters to insert those pellets in electrical rotatory machineries.