Research On A New Type Of Viscous Fluid Damper With High Damping

During the entire life cycle of the satellite,the launching process is the most vulnerable stage.During the launch phase,the dynamic environment is harsh because the satellite is affected by the random vibration and transient impact of the launch vehicle.The aerospace industry mainly uses the whole-spacecraft isolation technology to place a vibration isolation system in the payload attach fitting(PAF)to reduce the various vibration and impact loads that satellites bear during the launching process and ensure the stable operation of the satellite and its related equipments.As a vibration control device widely used in various fields,the viscous fluid damper can be used as the basic component of the payload attach fitting to achieve the damping efficiency,and effectively improve the satellite's vibration response at the launching process.However,the existing viscous fluid dampers have a complicated structure and poor sealing,the vibration isolation is not ideal in the low-frequency micro-amplitude range.In this paper,a new type of high-damping viscous fluid structure is designed.As a basic unit of the viscous fluid dampers used in the whole-spacecraft isolation field,it has a structure that maintains a small deformation in the longitudinal direction to keep stiffness output,and enlarges the lateral displacement to improve the damping effect.This structure,as a passive vibration control device,solves the problems of the complex structure and poor sealing property of the existing viscous fluid dampers.The structure is simple,easy to replace,and the damping characteristics can be adjusted by changing the viscosity of the fluid.In this paper,ANSYS + FLUENT software is used to perform mechanical and two-way fluidstructure interaction finite element analysis of the high-damping viscous fluid parts.Structural parameters are optimized by mechanical simulation analysis;a simple harmonic analysis of the filled fluid assembly was carried out to determine the design scheme for reducing the hydraulic diameter of the inner cavity to improve the damping output;in addition,it provides a theoretical basis for numerical analysis by establishing the mathematical model of the flow.Two structural improvement schemes are proposed,and the structure with circular through holes with obvious damping output is selected for fluid-structure coupling simulation analysis;the relationship between the parameters of the solid area and the fluid area and the vibration frequency is analyzed,and the equivalent damping coefficients at different frequencies show that the improved part has a higher damping coefficient than the original one;the effect of the circular through holes' parameters on the damping output is analyzed.The viscous fluid filling device and the high-damping strip-shaped assembly were designed and processed.The damping output of the strip-shaped assembly under dynamic loading was tested by the experiment.The test shows that the strip-shaped assembly has fuller hysteresis curves at low frequencies and better energy dissipation effect,as the frequency increases,the equivalent damping coefficient shows a decreasing trend as a whole,and it slightly rises in the high frequency band;the numerical simulation of the strip assembly shows that the assembly composed of improved parts has better damping output performance.This research has a good reference value for the design optimization of high stiffness and high damping parts and the application of the viscous fluid dampers in the field of vibration reduction and isolation.