Abstract
In this paper, we investigate the primary resonances of nonlinear dynamics of a horizontally supported Jeffcot rotor with relatively large umblance. The nonlinear normal modes are investigated from the averaged equation.natural frequency of the frequency. Because the linear stiffness in the horizontal and vertical directions is slightly difference due to the gravity, the backbone curve is much more complexted than the vertically supported rotor and bifurcation of the backbone cureve produces modes whose number is greater than the degrees-of-freedom.. We theoretically clarify the relationship between the frequency response curve of the horizontally supported rotor in the primary resonance and the backbone curves. Furthermore, we experimentally confirm the existence of the complex frequency response curve which is related to the nonlinear normal nodes.
