Study On Magneto-rheological Visco-elastomer And Its Application To Suppressing Micro-Vibration Of Sandwich Plates

Magnetoreological visco-elastomer (MRVE) and it’s application to suppressing micro-vibration of sandwich plates is discussed in this paper. Firstly, the isotropic Magnetoreological visco-elastomer samples are fabricated with magnetic particle and nonmagnetic matrix. Rigidity of MRVE increases with external magnetic field through the stress-strain relationship of MRVE. The mathematical relationship between modulus of MRVE and mass ratio of carbonyl iron powder is also obtained from experiment data.Secondly, MRVE are used to construct a smart sandwich plate for micro-vibration control of vibration-sensitive precise facilities under random support motion excitations. The dynamic behavior of MRVE can be described with a complex modulus which is depended on the excitation frequency and external magnetic field. According to theory of plates and shells and dynamic equilibrium, constitutive and geometric relations, the partial differential equations of motion of sandwich plates under random support motion are obtained. Galerkin method is applied to expand the differential equations into ordinary differential equations. The random micro-vibration response analysis method for viscoelastic sandwich plate is developed based on the frequency-response function, response power spectral density and root-mean-square velocity spectrum of the theory of random vibration. The effect of parameters and thickness of MRVE and size of sandwich plate on the root-mean-square (RMS) velocity are investigated by a large number of numerical computations. Results show that MRVE can greatly reduce the response of sandwich plates. In additional, the sandwich plates are not completely covered by the magnetic field in reality. The micro-vibration equations of sandwich plates under local magnetic field are derived based on separation of shear complex modulus of MRVE. The results are given to illustrate that response reduction capacity of the MRVE sandwich plates under compete magnetic field is not better than the sandwich plates under local magnetic field.Finally, Effect of trapezoid excitation which is applied to simulate support motion excitation on the response of sandwich plate is also studied. The simulation results indicate the response of MRVE sandwich plate is greatly reduced in the high-frequency range.