Dynamics and vibration reduction performance of a motion amplified nonlinear energy sink

Abstract

Suppressing micro-amplitude vibrations is an urgent issue that needs to be addressed in aerospace engineering applications. Nonlinear energy sink (NES) has shown remarkable performance as an effective passive vibration damping device. However, the NES’s performance is less effective when dealing with micro-amplitude vibrations. This paper proposes a motion-amplified NES (MANES) that can suppress micro-amplitude vibrations in the primary system. The governing equations of the system are derived using the Hamilton’s principle. The approximate analytical solution of the equations is obtained and validated by numerical methods. The effects of different parameters are discussed, and higher vibration reduction efficiency can be obtained by adjusting system parameters. The results are compared with those of a cubic NES (CNES) under the same parameters. It is found that due to stronger nonlinear factors, the coupled system with MANES may exhibit higher branching responses under harmonic excitations. However, the MANES demonstrates superior vibration suppression performance and a wider vibration reduction bandwidth when dealing with micro-amplitude excitations. Moreover, with the increase of external excitation, MANES consistently enters the effective vibration reduction range earlier, indicating that MANES has a lower effective threshold for vibration reduction. This study reveals the vibration suppression mechanism of MANES, providing a theoretical basis for the suppression of micro-amplitude vibrations in engineering.