几何非线性黏性阻尼隔振系统的传递率特性

Transmissibility Characteristics of Geometrically Nonlinear Viscous Damping Vibration Isolation System

针对传统舰载非线性隔振系统中存在的抑制共振峰值和改善高频传递特性相矛盾的问题,首先,建立了包含非线性刚度、库伦阻尼和几何非线性黏性阻尼的非线性隔振系统数学模型,采用谐波平衡法进行解析求解;其次,对比分析了线性阻尼、库伦阻尼和几何非线性阻尼对隔振系统传递特性的影响规律,进一步研究了激励幅值对不同阻尼隔振系统振动性能的影响;最后,通过振动试验进行了验证。结果表明:增加系统库伦阻尼,虽然能够降低软特性隔振系统共振区传递率,但会导致硬特性隔振系统出现“频率岛”现象,同时高频隔振性能下降,而且随着激励幅值的增加,共振区隔振性能随之变差;增加系统几何非线性黏性阻尼,不仅能够有效降低共振区传递率峰值,而且能够保证高频区良好的隔振性能;几何非线性黏性阻尼拓宽了系统对激励幅值的适用范围,为非线性隔振系统设计提供了指导作用。

Aiming at the contradiction between suppressing resonance peaks and improving high-frequency transmission characteristics in traditional shipborne nonlinear vibration isolation systems.First,a mathematical model of the nonlinear vibration isolation system containing the nonlinear stiffness,Coulomb damping and geometric nonlinear viscous damping is established,and the harmonic balance method is used to solve the problem analytically.Then,the influence of linear damping,Coulomb damping and geometric nonlinear damping on the transmission characteristics of vibration isolation system is compared and analyzed,and the influence of excitation amplitude on the vibration performance of different damping vibration isolation system is further studied.Finally,the vibration test is used to verify.The results show that increasing the Coulomb damping of the system can reduce the transmission rate of the soft vibration isolation system in the resonance zone,but the phenomenon of"frequency island"appears in the hard vibration isolation system,and the high-frequency vibration isolation performance decreases at the same time.Moreover,as the excitation amplitude increases,the vibration isolation performance of the resonance zone becomes worse;Increasing the geometric nonlinear viscous damping of the system can not only effectively reduce the peak transmission rate in the resonance region,but also ensure good vibration isolation performance in the high frequency region;At the same time,geometric nonlinear viscous damping broadens the system′s applicable range of excitation amplitude,and provides an important guidance for the design of nonlinear vibration isolation systems.