Study On The Effect Of Coupling Negative Stiffness On Energy Sink Vibration Reduction

With the development of aerospace technology,the structural dynamics environment becomes more and more complicated in the multiple aerospace missions.This dissertation focus on Nonlinear Energy Sink(NES),which is the vibration suppression of spacecraft.On the basis of the existing research,this dissertation illustrates in a new structural form,namely the NES with coupled negative stiffness,and the author analyzed its vibration reduction effect and dynamic characteristics based on the nonlinear dynamic theory.The specific content includes the following aspects:To resolve the vibration issues of coupled negative stiffness energy sink(CNSES)in undamped conservative system,the author concluded the systematic slow-varying flow model which was derived from the complex variable-average method,and studied the initial energy conditions of triggering target energy transfer by coupled negative stiffness energy sink according to the slow-varying flow model.Meanwhile,the author studied the nonlinear modes in the system,and divided the systematic initial conditions into different energy levels based on the frequency energy diagram in the system.Besides,the author studied the response mechanism of the system at different initial energy levels by numerical integration and poincare mapping.To resolve the vibration issues of CNSES in damped dissipated systems,the author studied resonance capture phenomenon of energy transfer in the system by using the slow-varying flow model and the phase trajectory equation.The author compared vibration reduction efficiency of CNSES with the traditional cubic stiffness energy sink(CSES)under different parameters through the systematic vibration reduction efficiency.By means of numerical integration,the author established the energy change diagram of CNSES and the energy change diagram under the topological structure of double sinks.To resolve the vibration issues of CNSES under harmonic excitation,the author studied the saddle junction bifurcation of the system and analyzed the influence of different excitation frequencies and negative stiffness values on the equilibrium point of the system.The author also studied the response mechanism of NSES and CSES system through manifold analysis and comparison of phase trajectories.