Study On The Parameters Of Vibration Attenuation And Energy Robustness Of Track Nonlinear Energy Sink

Frequent earthquakes have seriously affected the safety of human life and property.It is a difficult problem for human beings who have no choices but to face with to ensure the stability of the structure under extreme loads.People usually resist the destruction of structures under extreme loads by strengthening the structures in the past,but this method is not economical and dangerious.So the structure control technology emerges in this case.Tuned mass damper is a passive control device which is commonly used.But its development is limited to be sensitive to structural frequency changes.Nonlinear energy sinks(NESs),a type of nonlinear structure control device,can be effective to shifts in the structure's natural frequency and essentially solve the control device problem of being sensitive to frequency changes.The track NESs,a new type of NES,produce essential nonlinear restoring force by the curve track and has a stronger nonlinearity than type ? NES.The track NES can reduce the response of the structure to a similar level as much as TMD and remained robust against detuning in the structure.Based on the track NES,Single-Sided Vibro-Impact(SSVI)track NES provides nonlinearity by both a nonlinear force-displacement relationship and a discontinuous restoring force.The discontinuity in the restoring force is realized through vibro-impact by adding an impact surface on one side of the NES mass.SSVI track NES is more robust against changes in the underlying structure than the TMD and show great robustness against the input energy level.The parameters of track NES and the robustness against the input energy level are investigated in the paper.The parameters of SSVI track NES under seismic excitations are further investigated.The main research contents and conclusions are as follows:1.The damping of the track NES under impulse load is investigated and analyzed.The influence of NES damping on the performance and robustness of vibration attenuation are discussed.The parameters of track NES under seismic excitations are optimized.The results show that the damping of the track NES can be optimized to maximize the vibration attenuation efficiency and robustness of the NES.The track NES optimized under seismic excitations show great performance of vibration attenuation.2.A secondary optimization is performed on the seismic attenuation parameters of SSVI track NES,including the coefficient of restitution and the clearance between the impact surface.The results show that the performance of SSVI track NES under seismic excitations can be further improved by the optimization.The parameters of SSVI track NES should be designed according to the frequency distribution of seismic.3.The track shape of track NES is studied.The vibration attenuation robustness of track NES under different track shape functions is discussed.Based on the three-order-polynomial track NES,double-segment(DS)track NES is proposed.The performance and robustness of vibration attenuation of DS track NES are also analyzed.The three-order-polynomial track NES performs well and exhibits stronger robustness against changes in structural stiffness,and show great energy robustness when the input energy is in higher level.DS track NES show great energy robustness whatever the input energy is higher or lower.