Research On Magnetorheological Elastomer Material And Device For Transverse Vibration Control

Currently, the requirement of building structure against wind and vibration has become higher and higher. As a continuation of the traditional seismic protection technology, the base isolation has become one of the most innovative structural antiseismic technologies in 21 st century. The destructional form of seismic wave is embodied in transverse wave which manifest himself by shaking back and fronth, the transverse wave is uncertain and time variant, while the performance parameters of traditional isolation system are fixed, which cannot be adjusted according to the change of external excitation and load. Therefore, there are great limitations with the employment of traditional isolation system. In recent years, with the purpose of overcoming the defects of the traditional isolation device, the magnetorheological elastomers(MREs) were proposed consecutively to be used in seismic field by international researchers and engineers. The modulus and loss facter of MRE can be changed rapidly and continuously by adjusting the external magnetic field. As a result, MRE has great potential in the field of vibration reduction, noise reduction and structural anti-seismic.A novel type of isolation bearing for the application of multi-layers flexible frame was manufactured in this article, which based on the preparation and performance characterization of the MRE. In addition, simulation research on semi-active control was carried out on account of the dynamic mechanical properties of the designed isolation bearing. The main content of this paper includes:(1) Based on the matrix, particles and auxiliary additives, this paper is committed to developing a high-performance MRE applied in seismic field with different raw materials and preparation process. In addition, effects of matrix types and curing magnetic field on the dynamic mechanical properties of MRE were also studied to further optimize the ratio and preparation method.(2) Effects of particle surface modification on the properties of MRE were explored, the carbonyl iron powder was coated with uniform and continuous Fe nanostructures which generated by a chemical reduction reaction. Moreover, the magnetorheological and damping property of the dimorphic MRE were studied systematically through partial substitution of CI particles with modified composite particles.(3) Magnetic circuit design and assembly process were optimized by the aspects of working mode selection, material selection and magnetic circuit analysis, and then realizing the manufacture and assembly of the novel laminated MRE isolation bearing.(4) The testing platform of the MRE bearing was built to study its dynamic mechanical response characteristics, from which can obtain the transmission characteristics and force-displacement relationship under different excitation currents, displacements and frequencies. According to the transfer characteristics, the frequencyshifting characteristics of the bearing were analyzed, and the peculiarities of stiffness and damping of the device were calculated through the relationship of displacement and force.(5) According to the model of multi-layers flexible frame, The vibration isolation system was studied from the description of model, design of controller and analysis of system performance. The seismic wave responses of displacement and acceleration were analyzed and compared with different control algorithms(passive, on-off, linear quadratic regulator(LQR)), in which the structural displacement and acceleration response were chosen as the evaluation indexes of the control effect.