双腔液固混合介质隔振器刚度阻尼特性分析

Stiffness and damping properties of dual-chamber liquid and solid mixture vibration isolator

双腔液固混合介质隔振器由波纹管式液固混合介质隔振器和附加腔室通过管道联通构成。建立了联通管道内部液柱的运动方程,推导了隔振器非线性动力学模型。为分析隔振器刚度和阻尼特性,将平方阻尼简化成线性阻尼,得到了简谐激励下隔振系统线性简化模型,并求得了隔振系统刚度和损耗因子的表达式。分析了阀门节流开度、振动幅值、激励频率、主腔室刚度对于系统刚度和损耗因子的影响。结果表明,虽然隔振系统刚度和损耗因子受多种因素影响,但是二者上下限只由两个腔室的等效刚度决定。为检验理论模型,进行了动态特性试验,试验结果和理论结果基本一致,证明了动力学模型的可靠性,试验结果还表明液柱共振会造成刚度特性曲线出现峰值,恶化系统的隔振特性。

The Bellows type Solid and Liquid Mixture （B-SALiM）vibration isolator,mainly proposed for vibration isolation of heavy machines with low natural frequency is formed with a multi-layer bellow container filled with SALiM working media including elastic elements and incompressible liquid.The dual-chamber SALiM vibration isolator is a B-SALiMvibration isolator linked with an incompressible pressure vessel by a tube and a valve.Based on the knowledge of fluid mechanics and dynamics,the nonlinear dynamics model of a novel vibration isolation system was established.To simplify the analysis of the stiffness and damping,a corresponding linear dynamics model and a complex stiffness were derived by simplifying the fluid damping into linear viscous damping when the isolator is excited by sinusoidal signal.A numerical simulation and an experiment were done to analyze the properties of the stiffness and loss factor.The results show that the stiffness and loss factor of the dual-chamber SALiMvibration isolator are affected by many factors such as the valve aperture /the main chamber stiffness/the exciting frequency/the vibration level and so on.The reliability of the nonlinear dynamic model was verified experimentally and the test results were generally consistent with the theoretical.It also can be illustrated from the experimental results that the oil vibration in the tube could cause bad effects on the vibration isolation effectiveness.