Metadamping in inertially amplified metamaterials: Trade-off between spatial attenuation and temporal attenuation

TL;DR

This paper demonstrates that inertially amplified metamaterials can achieve greater dissipation or reduced loss by coupling local resonance and inertial effects, enabling customizable trade-offs between spatial and temporal attenuation.

Contribution

It introduces a passive inertially amplified metamaterial design that enhances or reduces dissipation and reveals a tunable trade-off between spatial and temporal attenuation.

Findings

Inertially amplified metamaterials can surpass traditional damping limits.

Coupling local resonance with inertial effects enables performance trade-offs.

Design adjustments of lever angles control attenuation characteristics.

Abstract

Metadamping is the phenomenon of either enhanced or diminished intrinsic dissipation in a material stemming from the material's internal structural dynamics. It has been previously shown that a locally resonant elastic metamaterial may be designed to exhibit higher or lower dissipation compared to a statically equivalent phononic crystal with the same amount of prescribed damping. Here we reveal that even further dissipation, or alternatively further reduction of loss, may be reached in an inertially amplified metamaterial that is also statically equivalent and has the same amount of prescribed damping. This is demonstrated by a passive configuration whereby an attenuation peak is generated by the motion of a mass supported by an inclined lever arm. We further show that by coupling this inertially amplified attenuation peak with that of a local resonance attenuation peak, a trade-off between the intensity of spatial attenuation versus temporal attenuation is realized for a range of the inclination angles. Design for performance along this trade-off is therefore possible by adjustment of the lever angle. These findings open the way for highly expanding the Ashby space for stiffness-damping capacity or stiffness-spatial attenuation capacity through design of the internal structure of materials.