Vibration Suppression Of Axial Retractable Cantilever Composite Plate Based On NES

It is easy to induce vibration in the process of expansion of the retractable structure,which makes the production quality of the product,the control precision of the system and the reliability of the production operation greatly affected,so it is necessary to carry out vibration suppression,which has a high engineering practical value and significance.On the basis of previous studies,this study mainly uses composite laminates with axial retractable motion to simulate these retractable mechanisms in engineering,establish nonlinear dynamic equations and analyze dynamic characteristics.Nonlinear Energy Sink(NES)is used to study vibration suppression,and the vibration suppression effect is analyzed based on the principle of Target Energy Transfer(TET).The main research work is as follows:(1)Establishment of dynamic model for axial retractable cantilever composite laminates.Based on the first order shear theory and von Karman’s large deformation equation,a partial differential nonlinear dynamic equation of generalized displacement for an axially retractable cantilever composite laminar under the action of first-order aerodynamic pressure and in-plane harmonic excitation is established by Hamilton principle.(2)The solution of nonlinear dynamic equations and the analysis of dynamic characteristics.According to the displacement boundary conditions,the time-varying structural vibration modal functions were selected,and the nonlinear dynamic equations with time-varying coefficients in ordinary differential form were discreteted by Galerkin method.Where,the mass term,stiffness term and damping term in the equation all contain timevarying terms,which all change with time.MATLAB software was used to program and Runge-Kutta numerical method was used to analyze the dynamics characteristics.(3)Vibration suppression effect of nonlinear energy sink(NES)on axial retractable cantilever composite laminates.The nonlinear motion governing equation of a retractable cantilever composite plate attached with NES is derived.The partial differential equation of a nonlinear system with one degree of freedom is discretized by Galerkin method,and the nonlinear dynamic equation in ordinary differential form is obtained.The vibration attenuation effects of NES attached to the end of the retractable plate at different initial positions were compared by numerical method,and the vibration attenuation effects of NES attached to the end of the plate at different expansion speeds were analyzed.(4)Optimal design of nonlinear energy sink(NES).Increase the number of NES and connect them in series and parallel.The kinetic equation of the system with two kinds of energy sink is established by Hamilton principle.Using MATLAB programming,numerical solution and simulation were carried out to compare the suppression effect of a single NES,series NES and parallel NES,and to analyze and select the design scheme with the best vibration suppression effect.