Modal Identification of Superconducting Magnetic Levitating Bogie

A novel superconducting magnetic levitation transportation systems has been proposed at University of L’Aquila, Italy. The bogie floats due to a passive, self-balancing interaction between high temperature superconducting skaters on board and permanent magnets on the track, in all phases of motion, zero speed included. A scaled superconducting skater has been statically tested measuring the repulsive-attractive magnetic forces varying, in a controlled way, the distance between the skater and the track. A non linear hysteretic characteristic curve has been identified averaging a set of suitable measures. In a first step, considering the thinness of the hysteretic cycles, the characteristic curve has been simplified in a non linearly elastic one. On the same time the equivalent tangent stiffness of such a curve has been identified, knowing the geometry and the mass characteristics of the bogie, by an experimental modal analysis conducted in operational conditions. A companion numerical model of the system has been introduced to forecast the working conditions with particular attention to dynamic behavior.