新型准零刚度隔振器设计及动力学研究

Design and dynamic research of a new quasi-zero stiffness vibration isolator

针对传统被动隔振器低频隔振性能不足的问题,提出了一种连杆-倾斜弹簧负刚度机构,并将其与线性弹簧并联构成一种新型准零刚度(quasi-zero stiffness,QZS)隔振器。首先,对该隔振器进行静力学分析,建立无量纲力-位移和无量纲刚度-位移关系式,并讨论设计参数对隔振器刚度的影响,进一步得出隔振器在平衡位置处具有零刚度特性的参数条件;其次,通过动力学研究,建立隔振器在位移激励下的非线性动力学方程,并应用谐波平衡法推导出位移传递率;最后,采用四阶龙格库塔法对准零刚度隔振器在不同激励频率下进行数值仿真,并与不含负刚度机构的线性隔振器进行对比分析。结果表明,准零刚度隔振器在低频激励下的隔振效果明显优于线性隔振器,而在高频激励下具备与线性隔振器相当的隔振性能。

To improve low frequency vibration isolation performance of traditional passive vibration isolators,a negative stiffness mechanism containing links and inclined spring is proposed which and applied to a novel quasi-zero stiffness(QZS)vibration isolator by parallel connection with a linear spring.First,through the study of static characteristics,the relationship between the dimensionless force displacement and the dimensionless stiffness displacement of the vibration isolator is established.Besides,the effect of the geometric parameters on the stiffness is discussed and the parameter conditions in that the vibration isolator have zero stiffness are derived at the equilibrium position.Then,the nonlinear dynamic equation under displacement excitation is established by the dynamic characteristics,and the transfer rate is derived by the harmonic balance method.Finally,the vibration isolator is numerically simulated by the fourth-order Runge Kutta method,which is compared with the linear vibration isolator without negative stiffness mechanism.And the results show that the vibration isolator effect of the vibration isolator is obviously better than the linear vibration isolator under low-frequency excitation,and is equivalent to that of linear vibration isolator under the high-frequency excitation.