Research On Vibration Isolation And Impact Resistance Of A Limiter-Type Quasi-Zero-Stiffness Isolation System

Low-frequency vibration isolation has always been a hot topic for scholars.As a representative low-frequency vibration isolation technology,quasi-zero-stiffness(QZS)vibration isolation has attracted much attention in recent years.Due to the low natural frequency of the low-frequency vibration isolator,the relative displacement amplitude of the system is large when subjected to the shock load,which may even exceed the ultimate deformation of the vibration isolator itself,thus causing damage to the isolated equipment or its auxiliary connecting pipe system.Based on the QZS isolation system,this dissertation presents a limitertype QZS isolator to meet the demand for low-frequency vibration isolation and shock isolation in precision equipment in a harsh environment.The vibration isolation and shock resistance performance of the system were studied by combining theory with experiment.The following work has been conducted in this thesis:Firstly,a QZS isolation system with a double compression spring structure is proposed.The static characteristics of the system are deeply studied.Then,the QZS condition of the system is obtained.The approximate formula of the force-displacement expression is obtained by using the Taylor formula,and the error caused by the approximate expression is quantitatively analyzed.Secondly,to study the vibration isolation and shock resistance performance of the double compression spring QZS vibration isolator,the dynamic equation of the system under harmonic excitation was established and solved.The vibration transmissibility was taken as the vibration isolation performance index to study the influence of different parameters on the vibration isolation effect of the system.The results show that the low-frequency vibration isolation effect of the double compression spring QZS isolation system is better than the linear system.It is found that the acceleration response of the QZS system is smaller than the linear system,but its relative displacement response amplitude is larger.To solve the problem of large relative displacement response of the QZS system under the shock load,a limiter-type QZS isolation system was proposed.The working principle of the limiter-type QZS system was analyzed,the influence of the limiter parameters on the shock response was studied.The results show that the limiter-type QZS isolation system can effectively reduce the relative displacement response under shock load,and can effectively improve its shock resistance performance by matching reasonable limiter stiffness and damping parameters.Finally,the limiter-type QZS vibration isolator was designed and manufactured.According to the required test environment,the vibration and shock test-bed were built respectively,and the test results were analyzed.The test results show that the initial vibration isolation frequency of the system can be effectively reduced for the QZS structure,and the error between the test results and the simulation results under the shock load is small,which verifies the correctness of the simulation results.