Research On Performances Of Isolators Based On Deformation Adaptive Magnetorheological Elastomers

The machinery industry is gradually developing towards miniaturization and precision,and the requirements for mechanical vibration are getting higher and higher with the development of science and technology.The degree of mechanical vibration directly affects the stability and life of the equipment.In order to reduce the adverse effects of harmful vibrations on the equipment,the vibration isolator is placed between the vibration source and the vibration isolation device,which can effectively reduce the vibration intensity.The current isolators are mainly passive isolators,which can only work at a fixed excitation frequency,and the range and effect of the vibration isolation have certain limitations.Magnetorheological Elastomer(MRE),as a semi-active isolator,can adjust the stiffness and damping in real time through the magnetic field.It responds quickly to external excitation frequency and has larger vibration isolation range and better vibration isolation effect.Therefore,at present,it is a research hotspot in the field of material and vibration control.A new type of MRE(Deformation Adaptive MRE,DA-MRE)is proposed in this dissertation.The solidified magnetic field is designed according to the predefined deformation mode of MRE,so that the trend of grain chain can be adapted to the deformation mode.Based on the controllable mechanical properties of magnetorheological materials,a DA-MRE vibration isolator is designed.The mechanical properties of magnetorheological materials can be changed by changing the current in order to achieve the purpose of changing the vibration isolation performance of the isolator.The specific contents are as follows:The mechanism of magneto-elastic modulus of DA-MRE under compression mode was analyzed;the magnetic field control method of MRE particle structure under different working modes was proposed,and the shape of magnetic inductance line of magnetic field control device under tension and compression mode was simulated and analyzed using finite element software package;the preparation process of DA-MRE was established according to the performance requirements of magnetorheological materials of components.The relationship between magnetic field intensity and particle chains was obtained by analyzing the strength of solidified magnetic field.The shape of particle chains in DA-MRE was observed under a microscope.Based on the basic principle of isolator,a new type of DA-MRE isolator is designed.The magnetic circuit of the isolator was theoretically calculated and simulated.The mode of MRE was simulated and analyzed.The natural frequency of MRE can be obtained through analysis.which provides theoretical basis for the study,of the resonance region of the isolator.The overall structure of DA-MRE isolator was optimized and assembled.The magnetic field strength of the isolator at different current was measured by Tesla meter.The experimental system was built and the isolation performance of the isolators with different MREs were tested.The experimental results show that although the acceleration changes are different under different current,the isolation effect is better than that without control current under the range of 40Hz-90Hz.The isolator has a resonance phenomenon near 60 Hz and 90 Hz,and the isolation effect is poor.The DA-MRE isolator has better isolation performance than the ordinary MRE isolator.With the increase of the curvature of particle chain in the DA-MRE,the isolation range of the isolator is wider and the isolation effect is better.Based on the vibration isolation principle of MRE,a dynamic control method of MRE vibration isolator was proposed.The vibration isolation effect can be improved by adjusting the vibration and damping of the vibration isolators in the vibration signals of different phases.