Design,Analysis And Experimental Research Of A New Type Of Quasi-zero Stiffness Vibration Isolation System

Vibration isolation methods are usually used in engineering to reduce or suppress harmful vibrations.Traditional linear vibration isolation systems have been widely used,but they have the disadvantage of not being able to simultaneously have a high load-bearing capacity and a low initial vibration isolation frequency.Therefore,designing a nonlinear vibration isolation system that can overcome the shortcomings of traditional linear vibration isolation systems has become an important method to solve the problem of low-frequency vibration in engineering,and has very important engineering significance.Based on the related research of nonlinear vibration isolation systems at home and abroad,this paper studies and designs a new type of quasi-zero stiffness vibration isolation system with high static and low dynamic stiffness characteristics.It is composed of a negative stiffness mechanism and a linear spring in parallel.The mechanism includes leaf springs,movable levers and guiding structures.In this paper,the statics,dynamics and transmissibility characteristics of the vibration isolation system are analyzed,and the vibration isolation performance of the vibration isolation system is verified by the Runge-Kutta numerical method.And built a prototype of the vibration isolation system to verify the correctness of the theoretical analysis by conducting static and dynamic experiments.Specifically,the main research work and conclusions of this article are as follows:The mechanical structure of the quasi-zero stiffness vibration isolation system is designed and the design principle is clarified,and the static model of the vibration isolation system is deduced.By analyzing the restoring force-displacement relationship of the vibration isolation system with different structural parameters,the conditions that the structural parameters of the vibration isolation system need to meet when different static characteristics are realized are obtained.By solving the simplified dynamic model of the quasi-zero stiffness vibration isolation system,the frequency response characteristics of the system are obtained,and the judgment boundary of the system frequency response stability is calculated by the Mathieu equation discriminant method.Analyzing the transfer rate curves of the vibration isolation system under the two excitations,it is concluded that compared with the corresponding linear vibration isolation system,the quasi-zero stiffness vibration isolation system has better low-frequency vibration isolation performance.The fourth-order Runge-Kutta method is used to simulate and analyze the simplified dynamic model of the quasi-zero stiffness vibration isolation system,which verifies the correctness of the approximate analytical solution of the system under sinusoidal excitation.The response curves of the system in quasi-zero stiffness state under fixed frequency excitation,multi-frequency harmonic excitation,sweep frequency excitation and step excitation are studied.Comparing the results with the corresponding linear system,the quasi-zero stiffness vibration isolation system has an excellent low-frequency vibration isolation performance compared to the linear vibration isolation system.The static experiment is carried out on the vibration isolation system,and the experimental curve obtained is relatively close to the theoretical curve,which verifies the correctness of the static force model of the vibration isolation system;the correctness of the theoretical analysis is verified by the fixed frequency sinusoidal displacement excitation experiment at different frequencies.The experimental results show that the initial vibration isolation frequency of the quasi-zero stiffness vibration isolation system is about 1.5 Hz,which is less than the initial vibration isolation frequency of the corresponding linear system,indicating that the designed quasi-zero stiffness vibration isolation system has wider vibration isolation Frequency domain.