Multifaceted vibration absorption of a rotating magnetic nonlinear energy sink

Abstract

Hazardous failures of engineering structures can be prevented by implementing passive vibration absorbers. Although tuned mass dampers (TMD) are used most frequently in practice, nonlinear energy sinks (NES) offer a broader frequency performance due to their targeted energy transfer (TET) mechanisms. However, this behavior occurs only in a limited amplitude range. In this work, the vibration suppression of novel monostable and bistable magnetic rotary nonlinear energy sinks (MRNESs) are studied numerically and experimentally over a range of excitation magnitudes for impulse and harmonic excitation. The MRNESs are tuned to achieve hybrid TMD and NES-like behavior. The medley of in-well, cross-well, and rotational TET mechanisms responsible for their performance are related to their underlying Hamiltonian systems and lower boundaries of chaos. For impulse excitation, rotational, subharmonic, and nonlinear beat responses lead to efficient energy dissipation. For harmonic excitation, the MRNEs’ frequency responses can resemble a TMDs’ or exhibit chaotic-like cross-well and rotational strongly modulated responses. Consequently, MRNESs can overcome the shortcomings of many NESs, which are inefficient at low excitation magnitudes, while also outperforming linear TMDs when the systems’ parameters are detuned at large excitation magnitudes, for both impulse and harmonic excitation. The MRNESs’ TET mechanisms and efficient performance over a broad range of excitation magnitudes were validated experimentally for both types of excitation. The MRNES may be more viable for practical use than other hybrid NESs since it is compact, highly customizable, and does not rely on impacts or complicated spring arrangements for its non-linearity.