关键词: 低频扭振, 磁扭负刚度, 磁荷叠加, 隔振

Abstract: The low frequency torsional vibration, which can not only reduce the power transmission efficiency of the shaft struc-tures, but also threaten the operation safety of them, has been the research hotspot in the field of low frequency vibra-tion control. As the existing negative stiffness mechanism employed for low frequency torsional isolation in shafts suf-fers from the strong nonlinearity and low negative stiffness, thus the design of torsional isolator with high magnetic torsional negative stiffness is proposed via magnetic charge superposition. The high magnetic torsional negative stiff-ness composed of tiles magnetized circumferentially is connected with plane spiral spring in parallel to analyze the low frequency torsional isolation performance of the shaft structures. Refer to the magnetic charge model, the nonlinear torque and torsional negative stiffness of the high magnetic torsional negative stiffness spring are derived, and then demonstrated via the numerical simulation of finite element method in comparison with that of the traditional magnetic negative stiffness array. Besides that, the mechanical properties of plane spiral spring are also investigated using An-sys workbench. With the effects of above analysis, the governing equations of the proposed isolator can be estab-lished, and relevant low frequency isolation performance is studied with harmonic balance approach. Finally, a test rig of the isolator is set up to determine its low frequency torsional isolation performance. The experimental results show that the magnitude of high magnetic torsional negative stiffness spring is twice as high as that of the traditional mag-netic negative stiffness ones, which can significantly broaden the isolation bandwidth as well.

Key words: low frequency torsional vibration, magnetic torsional negative stiffness, magnetic charge superposition, vibration isolation