Metastructure-based system for micovibration mitigation

Microvibrations are low-amplitude mechanical vibrations with displacement levels ranging from the sub-micron to several microns. They span a broad frequency spectrum, typically from below 1 Hz to several hundred Hz and, in some cases, extending into the kilohertz range. Such vibrations can significantly affect the stability and reliable operation of vibration-sensitive systems such as precision instrumentation. Conventional isolation techniques, both passive and active, often face limitations in addressing low-frequency vibrations due to spatial constraints, structural complexity, or high cost. This study proposes a hybrid metastructure-based system for broadband microvibration mitigation. The system integrates locally resonant units embedded within steel tubes with high-damping laminated rubber bearings (LRBs), thereby combining bandgap-based attenuation in both directions with enhanced horizontal isolation and energy dissipation. The performance of the proposed system is evaluated through both frequency-domain and time-domain analyses using COMSOL Multiphysics. Results show that the system achieves effective vibration mitigation across a wide frequency range while maintaining a compact and efficient design, with performance comparable to selected commercial devices. Under broadband white-noise excitation, the proposed system reduces the acceleration response by 93.3% in the horizontal direction and 91.1% in the vertical direction. Time-domain evaluations further confirm that, for the investigated input levels, the one-third octave RMS velocity spectra remain below the Vibration Criterion D (VC-D) threshold developed by Colin Gordon and Associates. This criterion specifies an allowable root mean square (RMS) vibration velocity within a specified frequency range and is widely used for evaluating environments housing vibration-sensitive equipment such as scanning electron microscopes (SEMs). Overall, the modular configuration and ease of integration make the proposed metastructure system a practical solution for vibration mitigation of structure or equipment requiring stringent vibration control.