Research On Nonlinear Vibration Isolation System Based On System Identification

Vibration is usually considered to be negative in engineering practice such as vehicle vibration reduction.In practical engineering,vibration isolation technology is often applied in vibration reduction technology because of its advantages of low cost and easy implementation.However,in the design process of vibration isolation system,there are some difficulties in the design of nonlinear system under complex load.The OFRF(Output Frequency Response Function)based on system identification can solve this problem well.In this paper,a comprehensive transmissibility criterion is proposed to evaluate the isolation performance of nonlinear isolation systems under complex loads.Secondly,a kind of combined nonlinear isolator is introduced,and the performance of the combined isolator compared with other vibration isolators with different nonlinear forces is analyzed.The results show that the combined isolator has better isolation performance.In addition,based on the system identification theory,the expression of the OFRF of the comprehensive transmissibility is derived,and the design process of the nonlinear vibration isolation system based on the OFRF method is proposed.The simulation results show that the design can meet the design requirements of the vibration isolator under complex working conditions.The main research contents of this paper are as follows(1)Analyze the vibration isolation system energy of the linear vibration isolation system.The dynamic differential equation of linear system is established by force analysis,and the linear ordinary differential equation is solved by Runge-Kutta method.The performance analysis method of vibration isolation system is introduced.Then the influence of linear stiffness and damping on the vibration isolation performance of the system is discussed.The results show that the stiffness and damping of the linear vibration isolator are not good for the performance of the system.(2)A new evaluation criterion for the performance of vibration isolation system under complex load,the comprehensive transmissibility,is proposed.Firstly,an analysis and evaluation method for the overall vibration reduction performance of the vibration isolation system under different energy excitation signals under complex loads is proposed,and the formula expression and physical meaning are given.Then,based on the comprehensive transmissibility,the permissible design interval constraints of the vibration isolation performance of the nonlinear vibration isolation system are discussed in detail.(3)Dynamic analysis of several nonlinear vibration isolation systems under complex excitation and comparison of their vibration isolation performance.Firstly,the dynamic differential equations of several nonlinear systems are established and normalized by force analysis,and the nonlinear ordinary differential equations are solved by Runge-Kutta method.Then,based on the new evaluation index,the comprehensive vibration isolation performance of several vibration isolation systems is discussed,and the specific effects of system parameters on the system performance are studied.(4)Based on the OFRF,the design process of nonlinear stiffness damping system is proposed.Firstly,the OFRF method of the nonlinear system and the synthesis transmissibility is derived.Then,based on the relevant design constraints and using a set of input and output data of the nonlinear vibration isolation system,the relevant system design process is proposed to design the vibration isolation system.Finally,an example is given to verify the effectiveness of the design process.(5)Design and process an experimental platform of vibration isolator,and study the performance of vibration isolation-related structures through experiments.Because the nonlinear stiffness damping system studied has good performance,according to the mechanical model of the system,the nonlinear vibration isolation system experimental platform is designed,manufactured,and the experimental equipment of the vibration isolation system is set up.The effectiveness of the beam damping structure for the vibration isolation performance of the whole structure is verified by the statics and vibration excitation experiments on the test bed and the relevant experimental data are obtained.