Magnet based bi-stable nonlinear energy sink for torsional vibration suppression of rotor system

Abstract

This paper investigates the application of a magnetic bi-stable nonlinear energy sink (MBNES) on torsional vibration suppression of the rotor system. Firstly, the structure of the proposed nonlinear energy sink is introduced, which simultaneously combines a set of positive stiffness connecting rods with the overlapping magnet negative stiffness configurations together to produce the bi-stable characteristic. Furthermore, the analytical expression of the nonlinear torsional stiffness of the MBNES is derived by applying the magnetic charge theorem, and the dynamic model of the rotor-MBNES system is established in turn. Next, the vibration attenuation performances of the MBNES under transient and steady-state excitations are evaluated, respectively, and the parameter affections are studied. Finally, experimental studies are carried out on the coupled system. The results demonstrate that adding MBNES to the main system can obtain 2.22 times dissipating speed in transient response, and the vibration suppression rates of 65.68% in simulation and 54.10% in experiment are achieved in steady-state response.