Predicting the Endless Stop-Band Behaviour of the NS-MRE Isolator

The periodic structure of the MRE isolator could generate special frequency range in which the waves cannot be propagated. This paper proposed a Negative Stiffness Magnetorheological Elastomer (NS-MRE) isolator with acoustic metamaterial characteristics. This particular structure generates an endless stop-band to restrict the transmission of the vibration. Furthermore, the permanent magnet arrays in the periodic structures of the NS-MRE isolator add dynamic negative stiffness to reduce the overall stiffness in the horizontal vibration direction without sacrificing vertical load-bearing stiffness. That can solve contradictory requirements for large load-bearing capacity and excellent vibration isolation performance at low frequencies as the former requires for large stiffness and the later requires for small stiffness. Using the mass-spring model, the generation mechanism of the stop-band was theoretically analysed. This paper deeply analyses the difference between the NS-MRS isolator and MRE isolator, in particular the stop-band of the single-mass periodic structure from the perspectives of finite period and infinite period, and its potential application for attenuating vibration amplitudes.