A compact quasi-zero-stiffness device for vibration suppression and energy harvesting

In this study, a novel compact energy harvesting dynamic vibration absorber (EHDVA) with quasi-zero-stiffness (QZS) characteristics is engineered for both vibration suppression and energy harvesting under low frequency. The QZS EHDVA is composed of a negative stiffness magnetic spring (NSMS), a spiral flexure spring (SFS) and coils. Firstly, the analytical expressions of the force and stiffness of the NSMS are derived by using the equivalent magnetic charge method, and the restoring force of the SFS is analyzed with finite element method. The electromechanically coupled equations are then solved using the Harmonic Balance Method (HBM), and the effect of system parameters on both the performances of vibration suppression and energy harvesting is investigated in detail. Finally, the prototype of the QZS EHDVA is fabricated, and an experiment is carried out to verify the theoretical model. According to the testing findings, the QZS EHDVA is able to suppress vibration in the low frequency region between 3.7 Hz and 6.1 Hz. In addition, the maximum output power of 1.51 mW is achieved under a load resistance of 300Ω at a driving frequency of 4.5 Hz.