Three-Dimensional Mechanical Metamaterial for Vibration Suppression

Abstract

Decades of research have been conducted on vibration suppression, cancellation, and absorption methods. Recently, distributed arrays of resonators have been implemented in host structures creating devices termed mechanical metamaterials, also known in the literature as metastructures. The benefit of using mechanical metamaterials as opposed to traditional added absorbers is the structure is initially designed including the absorbers instead of adding them after creation, saving time and weight. Additionally, these structures remain capable of bearing loads without adding additional mass. Where past research has focused on designing and optimizing metastructures based on single degree of freedom excitations, the research presented in this paper focuses on a device capable of vibration suppression under excitation in three directions; longitudinal, transverse, and torsional. This accommodation is necessary for these devices to be implemented in non-laboratory settings to account for excitation from multiple directions.

This paper presents experimental data and a preliminary finite element model for a three-dimensional mechanical metamaterial vibration suppression system. Experimental results compare the structure with blocked absorbers to free absorbers to demonstrate vibration reduction bandwidths of 358 Hz in the longitudinal direction, 24 Hz in the transverse direction, and a frequency shift of 40 Hz in the torsional direction. These promising results show that a metastructure can be effectively designed to suppress vibrations in all three directions of excitation with further motivation to explore optimization of the absorber system for maximum suppression bandwidth.