含三次非线性位移的粘性阻尼干摩擦隔振系统振动特性的实验研究

在分析库仑摩擦阻尼双线性滞迟模型的基础上，通过试验建模和参数辨识，得到了无记忆恢复力亦为非线性力的动力学模型。金属橡胶粘性阻尼隔振系统对正弦基础激振的响应计算表明：在相对位移振幅ym较大的情况下，必须考虑无记忆恢复力中位移三次非线性的影响；而在ym较小时，位移三次非线性的影响可以忽略不计。金属橡胶粘性阻尼隔振系统的振动试验表明：粘性阻尼隔振系统的一阶共振频率随激励的逐渐增强而逐渐减小并趋于稳定；其一阶共振放大比随激励的增强先减小后增大，但变化的幅度不大，在激励较小时表现出明显的“软化”非线性动态特性，在较大激励时仍具有较好的隔振缓冲性能，验证了试验建模的结果。研究结果表明，金属橡胶精细结构材料具有很强的阻尼耗能作用，对恶劣环境下各种仪器设备的振动保护非常有利。

EXPERIMENTAL STUDY ON A VIBRATION ISOLATION SYSTEM WITH VISCOUS DAMPING AND CUBIC NONLINEAR DISPLACEMENT

Based on analysis of a bilinear hysteretic model with Coulomb friction damping, a new dynamic model with nonlinear memoryless restoring force is obtained by experimental modeling and parameter identification. The response calculation of a metal rubber vibration isolation system with viscous damping and simple harmonic excitation indicates that if the relative displacement amplitude ym is larger, the effect of the cubic nonlinear restoring force has to be considered; in contrast, if ym is smaller, the effect can be ignored. The corresponding vibration experiment validates that the first order resonance frequency of a vibration isolation system with viscous damping decreases gradually with excitation streng thened and closes to a stable value; the first order resonance magnification ratio decreases firstly and then increases with excitation streng thened, but the changing magnitude is not big. All these prove that the theoretical analysis is true and the experimental modeling is correct. Moreover, the study results show that metal-rubber structural material has a strong ability of energy-dissipation, which is very useful and significant to vibration isolation of various instruments under bad environment.