Modelling And Dynamic Analysis On Nonlinear Quasi-zero Stiffness Vibration Isolator With Vibration Absorber

With the development of intelligent vehicle,a large number of vehicle precision instruments and electronic equipment are assembled on the vehicle.Vehicle mounted high-precision equipment is more sensitive to low-frequency excitation,so it is necessary to design vibration isolator to reduce low-frequency vibration and improve vehicle ride comfort.In this paper,a kind of vehicle nonlinear quasi-zero stiffness Vibration Isolator with Vibration Absorber(VIVA)is designed,in which the negative stiffness mechanism is composed of tension spring and cylinder block,which is connected in parallel with the positive stiffness compression spring,and then the damping vibration absorber is connected in parallel to form a complete system.Through the static analysis of a single quasi-zero stiffness isolator,the range of system parameters with zero stiffness in the quasi-zero stiffness isolator negative stiffness mechanism is obtained,and the influence of system parameters on the zero characteristics of quasi-zero stiffness isolator negative stiffness is studied.The average method is used for dynamic analysis,and the approximate solution of the amplitude frequency response of the system is obtained.The response of the vibration isolation system under simple harmonic force and simple harmonic displacement excitation is compared.The effects of excitation amplitude,Coulomb friction in negative stiffness mechanism,pretension distance,stiffness ratio and damping ratio in positive stiffness mechanism on the amplitude frequency response and transmissibility of the vibration isolation system are studied.On the basis of this,the dynamic vibration absorber and the quasi-zero dynamic vibration absorber are designed.The dynamic analysis of two different vibration absorbers is carried out by multi-scale method,and the approximate amplitude frequency response equation is obtained and compared.At the same time,the influence of the system parameters of the quasi zero stiffness vibration isolator on the amplitude frequency characteristics and force transmissibility of the main mass is studied.Through comparison and numerical solution verification,it is proved that the performance of quasi zero stiffness isolator is greatly improved after adding vibration absorber.A quasi-zero stiffness vibration isolator is designed and manufactured.The displacement response of the main mass of the quasi-zero stiffness vibration isolator is tested under different harmonic displacement excitation.The experimental data are collected by laser displacement meter and acquisition instrument to verify the correctness of the theoretical results.In addition,the quasi zero stiffness vibration isolator system is paralleled with the wheel motor-driven electric vehicle 1 / 4suspension to study the vehicle ride comfort at different speeds.The results show that:(1)the quasi-zero stiffness isolator can effectively reduce the vibration caused by low frequency excitation;(2)the addition of damping absorber can effectively improve the strong resonance of quasi-zero stiffness isolator,and the resonance peak is reduced by 25 %;(3)the feasibility of damping quasi-zero stiffness isolator is proved by experiments;(4)the quasi-zero stiffness Vibration Isolator with Vibration Absorber is better than the structure without vibration absorber,and the vertical amplitude of the main mass on the car body is reduced by 88.96% at least.The model and experiment in this paper have a certain reference value for the research of quasi zero stiffness isolator in the automotive field.