Band-stop characteristics of a nonlinear anti-resonant vibration isolator for low-frequency applications

Abstract

In order to broaden the vibration attenuation bandwidth of passive isolation systems in low-frequency applications, a nonlinear anti-resonant vibration isolator was studied by coupling a lever-type vibration isolator with a nonlinear vibration absorber. By appropriately designing the structural parameters, a wider double-attenuation stop-band emerges from the coupling of the levered mass and the absorber mass. Theoretical results show that the bandwidth of the proposed NL-AVI is much wider than that of an existing lever-type vibration isolator. A parametric influence investigation shows that the transmissibility and width of the stop band can be flexibly designed with structural parameters. The cubic nonlinearity of the vibration absorber has the effect of shifting the anti-resonant frequency and the resonant peak to higher frequencies, thereby increasing the stop band width. The proposed nonlinear anti-resonant vibration isolator provides a distinctive mechanical mechanism for realizing a combination of band transmissibility and width in the vibration attenuation characteristics and has been successfully validated by experimental prototypes for their advantageous performance in low-frequency vibration isolation.