Design And Research Of A Quasi-Zero Stiffness Isolator Based On The Double-V Metamaterial

The Sichuan-Tibet Railway starts from Chengdu,Sichuan Province in the east and ends in Lhasa,Tibet Autonomous Region in the west.The whole line has "six ups and six downs",with violent ups and downs.In this environment,the low-frequency vibration caused by non-linear factors such as gap,friction and large deformation in high-speed running locomotives brings great challenges to the safety and ride comfort of high-speed running locomotives.However,the traditional isolation system can not have lower natural frequency and higher bearing capacity at the same time.The quasi-zero stiffness vibration isolators with high static stiffness and low dynamic stiffness has small static displacement and low inherent frequency,which can effectively isolate low-frequency vibration.In this paper,the negative stiffness system is constructed depended on the properties of the negative Poisson’s ratio single-cell structure in metamaterial structures.Based on the negative stiffness system and the positive stiffness system,a quasi-zero stiffness vibration isolator is designed.The theoretical and experimental results show that the designed quasi-zero stiffness isolator can effectively solve the low frequency vibration isolation performance.Specifically,the following aspects are included.The possibility of constructing negative stiffness system is discussed based on the negative Poisson’s ratio structure.The relationship between the negative stiffness and the negative Poisson’s ratio of the classical concave hexagon is analyzed.According to the calculation results of negative Poisson’s ratio of single cell structure the influence of relevant parameters on the performance of negative Poisson’s ratio is discussed,and it is concluded that negative stiffness system can be constructed by using negative Poisson’s ratio structure.Furthermore,for the stability of the structure a new type of quasi zero stiffness isolator is designed by introducing a double-V concave six deformation structure.The relationship between the vibration isolation effect of the new quasi-zero stiffness isolator and different parameters is analyzed,which provides a theoretical basis for the construction of the required vibration isolation system.Based on the double-V concave hexagonal negative Poisson’s ratio cell structure,a quasi-zero stiffness vibration isolation system is designed,and the vibration isolation performance is studied.According to the vibration control equation,the static and dynamic characteristics of the quasi-zero stiffness system are analyzed,and the influence of some parameters on the vibration isolation performance of the vibration isolation system is discussed.The parameter optimization research is carried out,and the optimal parameters to achieve quasi zero stiffness are obtained.Furthermore,the vehicle seat human model is constructed to further verify that the vibration isolation effect of quasi zero stiffness seat is better than that of linear vibration isolation seat.According to the designed mechanical model of quasi-zero stiffness vibration isolator,two kinds of quasi zero stiffness vibration isolators are manufactured and tested.The vibration test platform is built and the vibration isolation performance test is carried out.The theoretical results of the influence of parameters on the vibration isolation effect are verified,and the transmissibility of the system under harmonic excitation is obtained.The results show that under the same excitation conditions,compared with the traditional nonlinear isolator,the resonance frequency and initial isolation frequency of the quasi zero stiffness isolator are lower than those of the traditional nonlinear isolator,and the quasi zero stiffness isolator can enter the initial isolation region faster than the traditional nonlinear isolator.