Modal bifurcation in a high-T-c superconducting levitation system

作者：Taguchi D^*; Fujiwara S; Sugiura T

来源：Superconductor Science and Technology, 2011, 24(5): 055006.

DOI：10.1088/0953-2048/24/5/055006

This paper deals with modal bifurcation of a multi-degree-of-freedom high-T-c superconducting levitation system. As modeling of large-scale high-Tc superconducting levitation applications, where plural superconducting bulks are often used, it can be helpful to consider a system constituting of multiple oscillators magnetically coupled with each other. This paper investigates nonlinear dynamics of two permanent magnets levitated above high-Tc superconducting bulks and placed between two fixed permanent magnets without contact. First, the nonlinear equations of motion of the levitated magnets were derived. Then the method of averaging was applied to them. It can be found from the obtained solutions that this nonlinear two degree-of-freedom system can have two asymmetric modes, in addition to a symmetric mode and an antisymmetric mode both of which also exist in the linearized system. One of the backbone curves in the frequency response shows a modal bifurcation where the two stable asymmetric modes mentioned above appear with destabilization of the antisymmetric mode, thus leading to modal localization. These analytical predictions have been confirmed in our numerical analysis and experiments of free vibration and forced vibration. These results, never predicted by linear analysis, can be important for application of high-Tc superconducting levitation systems.

• 出版日期2011-5