Study on the Mechanism for Line Spectrum Reduction in Nonlinear Vibration Isolation System

The chaotic response and mechanism for line spectrum reduction in nonlinear vibration isolation system are studied. The harmonic balance method is applied to uncover the interaction between different harmonics. It is clear that the considerable energy transfers from the fundamental harmonic to the others by the nonlinear interactions, and thus the energy at the dominant frequency is reduced greatly. When the nonlinear vibration isolation system is in a chaotic state, the response is characteristic of the broadband spectrum, and thus the energy is distributed to all the frequency components. Chaotic attractor is different from the point, limit cycle and so on, and the fractal dimension can be applied to describe its characteristic. Furthermore, the chaotic signal is distinguished from the random one by the saturation of the correlation dimension. The former approaches to saturation with the increasing embedding dimension, but the latter does not. The phase space reconstruction based on wavelet transform can achieve the study of both the geometry and frequency characteristics of the chaos, so that provides a new way to study chaotic response.