Research And Development Of STF-SF High Energy Isolation Bearing

Earthquake is a kind of natural disaster that is difficult to predict and has a great loss.It poses a serious threat to human life and property.The research on vibration reduction and isolation devices is an indispensable part of the field of vibration control.Shear Thickening Fluid?STF?is a new type of nano-composite material made of nano or micro particles.Under normal conditions,it appears as a uniformly dispersed liquid system with a certain fluidity.Under shear conditions,its viscosity It increases instantaneously with the increase of the shear rate and changes to a solid-like state with greater hardness.It has excellent energy absorption and energy dissipation performance,fast response speed and reversible process.In this paper,the rheological properties of shear-thickening liquids?MWNT/SiO₂-STF?in multi-walled carbon nanotubes?MWNT?and nano-silica?SiO₂?mixed systems with different mass fraction mixing ratios are studied.Influence of ambient temperature on rheological properties of MWNT/SiO₂-STF system.First,MWNT/SiO₂-STF systems with different concentrations?0.2-1.0wt%?were prepared by ultrasonic technology and mechanical stirring method.It was found by scanning electron microscopy?SEM?that MWNT had a strong adsorption effect on nano-SiO₂ and formed inside the mixed particles.The"new-type particle cluster"containing MWNT;then the MWNT/SiO₂-STF system was subjected to steady-state and dynamic rheological tests using a plate rheometer.The rheological test results show that the MWNT/SiO₂-STF system has a significant shear thickening effect,and when the MWNT mass fraction is 0.8%,the system has the best shear thickening performance,not only its viscosity can reach 170.23 Pa s,And has excellent energy storage and energy consumption capabilities.Finally,the influence of the plate gap and ambient temperature on the rheological properties of the MWNT/SiO₂-STF system shows that when the mass fraction of MWNT in the MWNT/SiO₂-STF system is low,the increase of the plate spacing not only significantly reduces its critical shear rate,It also significantly increased its peak apparent viscosity.More importantly,the temperature sensitivity of the MWNT/SiO₂-STF system is still dominated by SiO₂.While not affecting its temperature sensitivity,MWNT can significantly enhance the shear thickening performance of the SiO₂-STF system,and This system is suitable for the field of shock absorption and energy consumption,and can be used as a high-performance damping fluid.In view of the characteristics of seismic isolation technology for engineering structures,this paper presents an STF-SF high-energy-isolation isolation support suitable for STF groups.This support does not require external energy input,and has a simple structure,small size and mass.The advantages of lighter weight,low cost,and convenient construction make the protected engineering structure achieve better isolation effect.The STF-SF isolators are scaled down,and horizontal tests are performed based on the structural characteristics.The test results show that the STF-SF support works well with STF,and the shear thickening effect can occur at a loading speed of 1mm/s,and the response speed is fast.Among them,0.8%MWNT/SiO₂-STF damping fluid performs best,Provides 9.76kN damping force.