Isolation Characteristics Of The Solid And Liquid Mixture Isolator With Additional Chamber

The Solid and Liquid Mixture(SALiM)isolator with additional chamber is a novel isolator which is designed for vibration isolation of heavy equipment with low frequency.It consists of main chamber,additional chamber,and oil tube connecting the main chamber and the additional chamber.Fluid flowing back and forth in the tube can produce damping during system vibration.The filling amount of elastic element and the flowing space of the oil are increased by introducing the additional chamber.Thus reducing the stiffness of the isolator.According to the momentum equation of the fluid in the connected tube,the nonlinear dynamic model of the vibration isolator was established.The equivalent stiffness and damping expressions are derived by simplifying the nonlinear fluid damping into linear viscous damping when the isolator is excited by harmonic signal.The theoretical and simulation results show that the equivalent stiffness and damping of the system have complex properties.The internal flow of the connected tube is affected by the fluid damping force and the inertia force of the liquid column.Consequently,the isolator may show stiffness hardening or softening effects under various situations.Harmonic displacement excitation is applied to the vibration isolator through MTS fatigue testing machine.The effects of stiffness of main chamber and throttle opening on the dynamic properties of the isolator were studied.By comparing the simulation results with tested results verify the correctness of the theoretical model of the vibration isolator.The influence of the physical parameters of the vibration isolator on the dynamic characteristics of the vibration isolator is analyzed,which provides a reference for the further improvement of the vibration isolator.The frequency response characteristics of the vibration isolator under load was tested.A LabVIEW programme is developed for date acquisition and processing.The frequency characteristic curves of acceleration and hydraulic pressure of the vibration isolation system under the fast sweep excitation are obtained.The effect of throttle opening on the response characteristics of the system is studied.An online frequency identification method based on BP neural network is proposed,and adopt FEBC strategy carried out semi-active control simulation of vibration isolation system.