非线性迟滞阻尼对隔振系统力传递特性影响

摘要

To improve performances of a vibration isolation system,the influence of hysteretic damping caused by friction damping under nonlinear geometric condition on the force transmissibility of the system was investigated.Being different from the traditional single DOF vibration isolation model,an unconstrained 2-DOF vibration isolation model was built,containing the influence of the base mass.Its motion equation was solved by using the averaging method to get the frequency-amplitude equation. Then the expressions of the force transmissibility and the force-displacement transmissibility of the system were derived.It was shown that mass,damping and excitation frequency are the dominant parameters to influence the transmissibility;comparing to linear viscous damping,the hysteretic damping has a better performance to isolate vibration,it not only suppresses the resonance responses,but also improves the isolation performances at high frequencies.At last,a numerical solution of the force transmissibility for the motion equation with frequency-sweeping force excitation was calculated.The results showed that the simulation results agree well with the theorectical ones,the vibration isolation system with geometric nonlinear hysteretic damping has a better performance of vibration isolation.%为提高系统隔振性能，研究摩擦阻尼在几何非线性条件下产生的迟滞阻尼（结构阻尼）对力传递特性影响。区别于传统单自由度隔振系统，采用含基础质量影响的两自由度无约束隔振系统模型进行阻尼力特性研究。用平均法求解运动方程，获得系统频率-响应幅值方程，以此导出系统力传递率及力位移传递率表达式。理论结果表明，质量、阻尼与激励频率为影响传递率主要因素。与粘滞阻尼相比，迟滞阻尼隔振效果更好，不仅能降低共振区响应，亦能改善高频区隔振性能。对运动方程进行扫频激励下数值仿真，获得力传递特性数值解。结果显示仿真结果与理论结果吻合良好，几何非线性阻尼隔振系统具有良好隔振性能。