含机械调频式动力吸振器的准零刚度隔振系统隔振性能分析

Vibration Isolation Performance Analysis of Quasi-zero-stiffness Vibration Isolation System with Mechanical-frequency-modulated Dynamic Vibration Absorber

基于动力吸振器原理,在单自由度准零刚度隔振器基础上耦合可调频动力吸振器构成两自由度隔振系统.首先,对动力吸振器工作原理进行理论分析并提出其力学模型;其次,通过静力学分析,推导出系统满足零刚度条件时,各参数间的关系并分析其对系统刚度特性的影响;然后,建立两自由度隔振系统非线性动力学方程,利用谐波平衡法进行幅频响应解析分析,得到力传递率表达式;最后,数值分析动力吸振器阻尼、刚度、质量、激励力幅值和弹簧片有效长度对力传递率的影响规律,并与单自由度准零刚度隔振系统及两自由度线性隔振系统对比分析.结果表明:通过选择适当的动力吸振器参数不仅可以减小系统的起始隔振频率,增宽隔振频带,且还能加快系统力传递率在特定频段内的衰减速率,改善系统的低频隔振性能,实现激励频率的可适应性.

Based on the working principle of dynamic vibration absorption, a two-degree-of-freedom vibration isolation system is proposed by coupling the frequency-adjustable dynamic vibration absorber with the single-degree-of-freedom quasi-zero-stiffness vibration isolator. First, the working principle of dynamic vibration absorber is introduced, and its mechanical model is established. Second, through the analysis of static characteristics, a set of relations between the parameters of the system is derived when the system meets the condition of zero stiffness, and the influences of mechanical and structural parameters on stiffness characteristics of the system are studied. Then, the nonlinear dynamic equation of two-degree-of-freedom vibration isolation system is established. By using the harmonic balance method, the expression of force transmissibility of the system is obtained. Last, using the numerical analysis method, the effects of damping, stiffness, mass, excitation force amplitude and the effective length of spring on force transmissibility are numerically discussed. In addition, by comparing with the single-degree-of-freedom quasi-zero-stiffness vibration isolation system and the two-degree-of-freedom linear vibration isolation system, the vibration isolation performance of the system is studied. The results show that the designed two-degree-of-freedom quasi-zero-stiffness vibration isolation system can effectively reduce the initial vibration isolation frequency of the system, and the low-frequency vibration isolation performance of the system in different excitation frequencies can be improved by adjusting the parameters of the dynamic vibration absorber. Furthermore, by selecting appropriate values of damping, stiffness and mass of the dynamic vibration absorber, the effective vibration reduction frequency bandwidth can be further expanded, the attenuation rate of the system force transmissibility in a specific frequency band can be obviously accelerated, and the low-frequency vibration isolation performance of the system can be dramatically improved.