Analysis On Dynamic Characteristics Of A Quasi-zero-stiffness Vibration Isolation System Based On Euler Struct

Isolation plays an important role in industrial production, and requirements of that is increasingly stringent. In some industrial field, not only a high load carrying capacity is required, but also a wide range of vibration isolation frequency. It's difficult for a linear vibration isolation system to satisfy these two requirements at the same time, however, a kind of nonlinear vibration isolation called quasi-zero-stiffness system can have both high static stiffness and low dynamic stiffness characteristics, then the quasi-zero-stiffness system can overcome the contradiction and achieve the goal of low frequency vibration isolation.Since an Euler struct which subjects to axial pressure and transverse force may show a negative stiffness characteristic in some condition, then we can combine the Euler struct with a positive stiffness spring to form a vibration isolation system which can have both high static stiffness and low dynamic stiffness characteristics so as to achieve the goal of low frequency vibration isolation if parameters are appropriately chosen.The main contents of this paper are as follows:1.The static characteristic of an Euler struct which subjects to axial pressure and transverse force is analysed. The quasi-zero-stiffness system is reduced to an equivalent geometric nonlinear system so as to get the relationship between restoring force and deflection. By analyzing the transverse stiffness of the isolation system, the condition is determined to form this quasi-zero-stiffness system. And the adjusting method of maintaining the quasi-zero-stiffness characteristic is given when the load mass changes.2.The dynamic characteristic of the quasi-zero-stiffness system is analysed. Two dynamic differential equations are established when the system is overload or not overload.The steady state and amplitude frequency response of the system are also analysed. The harmonic balance method is used to solve the dynamic differential equations, and numerical method is also used to solve differential equations under several conditions.Through the analysis found that, the system has the characteristics of hardening spring and jumping phenomenon. But the jumping phenomenon can be avoided by adjusting the parameters.3.The force transmissibility and the absolute displacement transmissibility and the jumping phenomenon frequencies in these two cases are analysed. The force transmissibility defined by the average power of the system is calculated and these results are compared with that of the corresponding linear system of the quasi-zero-stiffness system. The conditions in which the vibration isolation performance of the quasi-zero-stiffness system is better than that of the corresponding linear system is given in this paper, and a brief analysis of the influence of parameters on the performance of vibration isolation is also given.