Design of Magnetorheological Dynamic Neutralizer for the Vibration Control under Broadband Excitation and Different Temperatures

Abstract

Viscoelastic dynamic neutralizers can successfully reduce the vibration of a mechanical structure called primary system. However, the viscoelastic materials used on those devices are sensible to temperature changes and this can detune the dynamic neutralizer, reducing its vibration control capabilities. Therefore, this work proposes a magnetorheological dynamic neutralizer which is optimally designed to reduce the vibration of a multi degree of freedom primary system under broadband excitation. At the same time, by changing the magnetic field applied to the magnetorheological material it is possible to mitigate the temperature changes in the neutralizer and its detuning. The modal parameters and frequency response function of the system are computed using a finite element model. The optimum design of the magnetorheological neutralizer is achieved by reducing the frequency response due to the optimal neutralizer parameters, natural frequency and position of the neutralizer on the primary system. The detuning is analyzed by increasing the operating temperature and by changing the magnetic flux density on the magnetorheological elastomer. This is provided by an electromagnet whose magneto-electrostatic behavior is simulated using a finite element method also. The results show a significant reduction in the neutralizer natural frequency with the rise of the material temperature and an inverse effect with the increase of the magnetic field. Furthermore, the detuned frequency response of the compound system, primary and neutralizer, is partially corrected for a higher magnetic flux density.