液阻悬置惯性通道阻尼特性的实验与计算分析

Experimental and calculation methods for determining damping properties of the inertia track in a hydraulic engine mount

以一轿车动力总成惯性通道型液阻悬置为研究对象,讨论了线性与非线性集总参数模型和模型中物理参数的特点及应用范围;应用流体力学有限元分析的方法,计算得到了惯性通道两端压力差与其中液体流动流量的关系,设计并制作了实验台,对计算结果进行了验证。利用惯性通道中液体流动的动量方程和惯性通道两端的压力差与其流量的关系,采用最小二乘方法,得到了惯性通道中液体流动的阻尼参数。该方法得到的阻尼参数,在较大激振频率和激振振幅范围内反应了惯性通道的阻尼特性。利用非线性的集总参数模型和本文方法得到的惯性通道阻尼特性参数,对一液阻悬置的动态特性进行了计算分析,计算结果和实验结果具有较好的一致性。

A Hydraulic Engine Mount （HEM） is an advanced vibration isolator, and is widely used as a vibration isolator in automotive powertrain, suspension, car body and other dynamic systems. The characteristics of the linear and the nonlinear Lumped Parameter （LP） models for an HEM with an inertia track and the methods for obtaining lumped parameters in the LP model are discussed in detail. A calculation method based on fluid finite element analysis for obtaining the relations of the pressure difference versus the fluid flow in the inertia track of an HEM are proposed, and the estimated relations are verified with the experimental data obtained from a special designed test rig. A lea：st squares method is used to calculate the lumped damping parameters of the LP model using the relations of the pressure difference and the fluid flow volume flux, and the steady-state momentum equation of the fluid motion in the inertia track. The calculated damping is based on all potential relations of the pressure difference between the two ends versus the flow volume flux of the fluid in the inertia track, so momentum equation of the lumped fluid mass in the inertia track agrees well with the actual motion of the fluid under different excitation conditions to the HEM. The dynamic performances of the HEM are estimated by using nonlinear LP mode along with the calculated damping parameters of the inertia track and the other systems parameters obtained by bench experiments. The calculated properties .of the HEM under different excitation conditions match well with the experimental data, which validates the method for obtaining the lumped damping parameters of fluid flow in the inertia track. The developed experimental and calculation methods for estimating the damping parameters are also instructive for modeling and analysis of other vibration isolators using the damping mechanism of the fluid through a channel.