A novel triple-magnet magnetic suspension dynamic vibration absorber

The existing Nonlinear Dynamic Vibration Absorbers (NLDVA) have the disadvantages of complex structure, high cost, high installation space requirements, and difficulty in miniaturization. And most of the NLDVAs have not been applied to reality. To address the above issues, a novel Triple-magnet Magnetic Suspension Dynamic Vibration Absorber (TMSDVA), only composed of triple cylindrical permanent magnets and an acrylic tube, is proposed in this paper. Firstly, the equivalent dynamics model of a TMSDVA cantilever system is established. A comparison of the simulation and experimental results serves to indicate that the suspended magnet will be "locked" when the instantaneous total energy of the system is less than a certain threshold. According to that, we modify the dynamics model. Next, the vibration reduction mechanism of the TMSDVA is revealed from the perspective of transient dynamics and energy. The TMSDVA can resonate with primary structures with different natural frequencies, so that the vibration energy can be targeted transferred to the TMSDVA and dissipated by the damping. Whether the acrylic tube has holes affects the damping of the TMSDVA, then the energy transfer between the primary structure and the TMSDVA and the energy dissipation rate of the TMSDVA, and ultimately the vibration reduction effect of the TMSDVA. By comparing the vibration reduction effects of the TMSDVA with holes and the TMSDVA without holes, we find increasing the damping coefficient appropriately can improve the vibration reduction effect of the TMSDVA, reduce the sensitivity of the vibration reduction effect to the excitation amplitude, and further enhance the robustness of the TMSDVA. Taken together, the TMSDVA has potential application value in the gravity direction vibration reduction of engineering structures.