Inertial-Amplified Mechanical Resonators for the Mitigation of Ultralow-Frequency Vibrations

We propose the design of a vibrational energy-absorption device based on the concept of inertial amplification, by utilizing coupling between translational and rotational motions. A compact and lightweight device, with dimensions being only 10--20 cm and weighing less than 1 kg, can achieve ultralow-frequency resonance response at seismic frequency range, i.e., 0.5--5 Hz. Resonators that can respond at such a low-frequency range are usually bulky structures on the civil-engineering scale; our compact design offers flexibility and options for practical applications. Fabricated functional prototypes verify the very large inertial-amplification factor, up to 137, through vibrational characterizations. Experimentally measured data are consistent with our analytical modeling of the inertial-amplification mechanism. Furthermore, we propose a structurally refined device configuration and demonstrate, through simulations, its capability of vibrational total absorption with a comparatively broadband working frequency range. Our design can be easily adapted for resonance frequencies up to 100 Hz, via further miniaturization of the device dimension and lowering of the inertial-amplification factor. The inertial-amplified resonator represents an unconventional solution to the difficult problem of ultralow frequency vibration mitigation, with compact and lightweight devices that can fit into limited space.