Research And Application Of Pore Characteristic Parameters And Intellectualization Of Viscous Fluid Damper

Viscous fluid damper(VFD)is widely used in military equipment,aerospace,ships,vehicles and other fields because of its simple structure,no stiffness,fast speed and good shock absorption effect.The damping performance of VFD depends on damping coefficient C and velocity exponent α.Traditional VFD is designed for a specific environment to optimize the structure parameters of fixed,the output range and energy dissipation capacity is limited,can not adapt to the external excitation,real-time adjustment,so the design of a damping continuously adjustable VFD,and applied to the semi-active control of vibration structure is of great significance.In this paper,the sensitivity of VFD structure parameters to damping performance is studied,and a kind of VFD with adjustable damping is designed and tested by experiments.At the same time,it is used in semi-active control of structural vibration based on Matlab/Simulink.The main contents of this paper are as follows:(1)Based on the Navier-Stokes equation,the energy dissipation principle of viscous fluid damper is analyzed,and the mathematical expressions of viscous fluid damper output of two types of structures(pore and gap)are derived.The nonlinear damping coefficient and the velocity exponent are transformed into the equivalent linear damping coefficient by the principle of energy equality,and the energy dissipation formula is obtained.(2)Based on Fluent flow field simulation,the damping performance of VFD is calculated and compared with the experimental results,the error is within ± 15%,which verifies the simulation accuracy.Based on the orthogonal design and Fluent simulation,the sensitivity of VFD structure parameters to damping coefficient and velocity exponent is analyzed,and the distribution of internal flow field is obtained.Compared with the traditional method of multi-prototype experiment,this method can reduce the number of design schemes,save the cost of experiment,and improve the efficiency of VFD design.(3)A new structural viscous fluid damper with continuous adjustable damping is designed.A by-pass oil path and a control opening are added to the cylinder of the traditional viscous fluid damper.The output formula of the new structure viscous fluid damper is further deduced by combining the formula of pore and gap damping forces.The principle of damping regulation of the structure is described in theory.The damping performance parameters under different openings are calculated by Fluent simulation,and the feasibility of the design is verified.At the same time,the experiment of the prototype is carried out regularly,which is consistent with the simulation results and achieves the expected goal.Finally,based on Matlab/Simulink,the simulation model of the adjustable viscous fluid damper,the dynamic simulation model of the monolayer frame system and the semi-active controller simulation model are established.