Inertial amplification of continuous structures: Large band gaps from small masses

TL;DR

This paper introduces a novel inertial amplification mechanism in continuous elastic structures, producing significantly wider and deeper band gaps at low frequencies with much less added mass than traditional methods.

Contribution

It demonstrates a new approach using inertial amplification to create large band gaps in continuous structures with minimal added mass, surpassing standard local resonator techniques.

Findings

Achieves wide, deep band gaps with twenty times less mass

Features unique dispersion curve characteristics like double-peak attenuation

Shows coalescence of gaps forming large contiguous band gaps

Abstract

Wave motion in a continuous elastic rod with a periodically attached inertial-amplification mechanism is investigated. The mechanism has properties similar to an "inerter" typically used in vehicle suspensions, however here it is constructed and utilized in a manner that alters the intrinsic properties of a continuous structure. The elastodynamic band structure of the hybrid rod-mechanism structure yields band gaps that are exceedingly wide and deep when compared to what can be obtained using standard local resonators, while still being low in frequency. With this concept, a large band gap may be realized with as much as twenty times less added mass compared to what is needed in a standard local resonator configuration. The emerging inertially enhanced continuous structure also exhibits unique qualitative features in its dispersion curves. These include the existence of a characteristic double-peak in the attenuation constant profile within gaps and the possibility of coalescence of two neighbouring gaps creating a large contiguous gap.