Design And Performance Test Of A Stage Damper With Magnetic Rate Control

Magnetorheological materials have become one of the most promising intelligent materials in the field of vibration control of Engineering structures.For large civil engineering structures,vibration control devices developed with intelligent materials can minimize the disasters caused by earthquakes.Shear thickening fluids(STFs)are a kind of functional fluids,whose rheological properties can be controlled by shear rate or velocity,which can make the damping mechanism adaptive,but its directional control goal has not been achieved yet;and magnetorheological fluid(MRF)can promote the realization of control goal under the effect of external magnetic field.Therefore,combining the advantages of MRF and STF,a new type of intelligent material,MR-STF,is proposed.The material has MR effect and shear thickening effect.It can be used as a normal "speed control" material and a "fault-proof" material without magnetic field.It will be of great theoretical significance and practical engineering value to develop a self-adaptive,self-reinforcing and self-adjusting vibration reduction actuator and apply it to the seismic vibration reduction of important engineering structures.Aiming at the defect that the traditional viscous damper has a single working frequency and can not be effectively controlled by different excitation frequencies,this paper develops a kind of impact energy dissipation damper with continuously variable damping,which can adapt to the environment of different vibration excitation frequencies.The dynamic mechanical properties of the developed damper are tested and the dynamic force applicable to the damper is established.Learn the model.The main contents of this paper include:1.Preparation and test of magnetorheological shear thickening fluid.The MR shear thickening fluid used in the damper was prepared by ourselves,and its dynamic mechanical properties were tested.The relationship between the viscosity of the material and the shear rate was analyzed under the condition of different magnetic field strength,as well as the change of the storage modulus and energy consumption modulus of the material with different iron particle mass fraction with the angularfrequency.2.Design and mechanical model research of magnetically controlled stage damper.According to different seismic conditions,a new type of magnetically controlled stage damper is designed in combination with magnetorheological shear thickening fluid.The damper is analyzed from the aspects of structural characteristics and technical indexes to meet the requirements of the preliminary design of the damper,the basic structural parameters of the damper are determined,and the mechanical model theory applicable to magnetically controlled stage damper is introduced.3.The finite element analysis of the stage damper with magnetic rate control.ANSYS and ABAQUS software are used to analyze the feasibility of the finite element simulation of the new type of magnetically controlled stage damper from the aspects of magnetic circuit and structure.Finally,the size and final design parameters of the damper are determined,and a full-scale magnetically controlled stage damper is manufactured.4.Performance test of magnetically controlled staged damper,and its dynamic mechanical model is established.The mechanical properties of the developed damper are tested under different displacement conditions,and the theoretical values are compared with the experimental results.The results show that the design is basically consistent with the expected design objectives,and the theoretical design is relatively feasible.At the same time,according to the dynamic characteristic curve of the magnetically controlled stage damper,the dynamic force of the magnetically controlled stage damper is established At last,the parameters in the mechanical model of the damper are identified.The results of numerical simulation and experiment show that the hysteresis characteristics,space phenomenon and the influence of disc spring on the damping force curve.