Development And Performance Study Of Semi-Active Isolation Bearings Based On Magnetorheological Elastomers

This article focuses on the current situation of frequent earthquakes in our country and the increased requirements for vibration control of floating objects/equipment due to technological development.It designs a semi-active control isolation support based on magnetorheological elastomer(MRE)material.This support has the advantages of low cost,good control effect,and suitability for isolating medium and small mass floating objects.The main research contents of this article are as follows:(1)Mechanical properties and microstructure of MRE materials with different formulations were studied.The optimal curing time,hardness,tensile strength,and elongation at break of MRE samples were determined through static mechanical testing,and the microstructure of the samples was observed using an electron microscope.Based on the mechanical properties of MRE materials and the distribution of the magnetic field,the dimensions of MRE isolation blocks and coils were designed and calculated.The magnetic field of the coil was simulated and verified using Ansys software.(2)A semi-active isolation support was designed,where four MRE isolation blocks were horizontally symmetrically placed with the design goal of aligning their center of mass with the center of the support.A counterweight block was installed on the upper part of the support to decouple the motion of the support.The vibration transmissibility of the isolation support was analyzed under three feedback modes: acceleration,velocity,and displacement.The displacement feedback mode was determined as the active control feedback mode for the support.The vibration model and dynamic equations of the support were derived,and the motion equations were simplified by designing the alignment of the center of mass with the center of the support.(3)Shear tests were conducted on MRE materials to quantitatively study the variation of their performance with magnetic field changes.Shear hysteresis curves of the four samples were obtained using the three-board shear method,and their variation patterns were analyzed.A Bouc-Wen model was established in Simulink software to fit the hysteresis curves,and the model parameters and control functions of the parameters were identified.Using the six mechanical performance indicators of the material as references,an error analysis was conducted on the measured data and fitted data,demonstrating the reliability of the fitting results.(4)The mathematical expression for the active control force of the support was provided,and the active control equation of the support was derived in conjunction with the dynamic equation.A simulation model of the active control equation of the support was established in Matlab/Simulink,and the designed 2D fuzzy controller was embedded.The controller takes the post-isolation displacement and velocity as inputs and outputs the coil current.A seismic input model was selected for simulation.The simulation results show that under fuzzy active control,the support can effectively isolate accelerations below 100mm/s~2 and significantly attenuate accelerations above 100mm/s~2.It also demonstrates good control effectiveness in terms of displacement.