Ultra-Low Frequency Vibration Isolation of Cockroach-Inspired Structures With Electromagnetic Shunt Damping Enhanced by Geometric Nonlinearity

Considering the limited vibration isolation performance of bionic structures under complex excitation environments, this work innovatively presents a cockroach-inspired structure (CIS) coupled with electromagnetic shunt damping (EMSD) for ultra-low frequency vibration isolation. The EMSD includes a linear EMSD embedded in a single coil for linear damping and a nonlinear EMSD with two opposite connected coils for nonlinear damping. The geometric nonlinearity of EMSD is achieved through the certain structural assembly, which is used to tune the damping properties of EMSD. The effects of geometric nonlinearity on the damping performance of EMSDs are investigated numerically and experimentally. Adjusting the geometric parameters and assembly configuration of EMSD can increase the electromagnetic coupling coefficient, resulting in enhanced equivalent damping. The experimental results demonstrate that the use of EMSD reduces the peak transmissibility of CIS from 1.9 to 1.47, without influencing the high-frequency vibration isolation significantly. This study provides a design methodology for the damping for bio-inspired vibration isolation structures.