Bandgap analysis of a tunable elastic-metamaterial-based vibration absorber with electromagnetic stiffness

Vibration is a mechanical phenomenon and exists throughout society. The vibrations in daily life would cause emotional discomfort as well as physical fatigue. Vibration even can give a life threat depending on its magnitude. Vibration is one of the significantly important factors to consider for the safety of the overall society, and therefore study of vibration reduction is indispensable. This paper presents a novel tunable electromagnetic vibration absorber based on an elastic metamaterial. The electromagnetic vibration absorber is a lattice structure dynamic model comprising elastic metamaterial unit cells having negative refractive index property and interconnected by springs. To verify the tunability of the elastic-metamaterial-based vibration absorber, the electromagnetic stiffness change in a finite element (FE) model of the electromagnet was analyzed through a parametric study of the air gap size, internal composition of the electromagnet, and amount of current. The conditions under which the electromagnet generates the highest electromagnetic stiffness were also explored. Each different value of electromagnetic stiffness obtained from the parametric studies was used for FE analysis of the dynamic model to investigate the influence on bandgap variations. The results reveal that the variation of electromagnetic stiffness has an effect on the location and bandwidth of bandgap. Moreover, vibration reduction was achieved due to the structural aspects of the dynamic model and the negative refractive index property of the elastic metamaterial. It is demonstrated that the elastic metamaterial vibration absorber is tunable in real time with the change of electromagnetic stiffness and has vibration reduction effect in various frequency ranges.