Effect of an additional mass on nonlinear resonance of a beam levitated over high-Tc superconducting bulks

This paper deals with effect of an additional mass on nonlinear resonance in a high-Tc superconducting magnetic levitation. The concept of an additional mass can be found in studies of various machines. In this research, using an elastic beam levitated above high-Tc superconductors, occurrence of internal resonance between the beam's two modes was investigated with respect to the mass position theoretically and experimentally. As a result, the beam's natural frequencies can change by the additional mass position. Accordingly, the frequency ratio between the 1st mode and the 3rd mode can be nearly 1 to 2 for a certain mass position. In that condition internal resonance between both the modes can occur by nonlinearity of the electromagnetic force. Its mechanism was explained theoretically, and its features were clarified by numerical analysis and confirmed by experiments.