【作者】 李林；

【导师】 上官文斌；

【作者基本信息】 华南理工大学 ， 车辆工程， 2013， 博士

【摘要】 液压衬套是应用在车辆底盘各系统与车身之间的新型隔振元件,是在橡胶衬套结构的基础上封装液体阻尼机构而形成的。其动态力学性能极大程度的满足了车辆的隔振要求,改善了整车的操纵稳定性和舒适性,且体积轻巧便于安装。目前,国内零部件生产厂商并没有从根本上掌握液压衬套开发的机理和技术,深入系统地研究液压衬套的设计理论与技术十分必要。本研究的主要工作为：1.实验研究了液压衬套静态、动态力学性能,探讨了实验测试方法和数据处理方法。对比分析了轴向型、径向型液压衬套的轴向及径向方向静刚度与轴向型、径向型橡胶衬套的轴向及径向静刚度的变化趋势；结果表明轴向和径向方向液压衬套的静刚度大于对应橡胶衬套的静刚度；测试研究了激励振幅及激振频率对轴向型、径向型液压衬套在轴向和径向方向的动力学特性的影响情况。在橡胶材料实验基础上,获得了不同应变状态下橡胶材料的应力-应变曲线。应用有限元分析中常见的3种超弹性本构模型,以最小二乘法拟合应力-应变曲线,识别得到各模型参数。以拟合误差最小的材料本构模型及其模型参数作为有限元计算的输入依据,为进一步液压衬套力学性能的计算奠定基础。2.基于实验测试结果,分别建立了轴向型、径向型单惯性通道式液压衬套动特性分析的集总参数模型,推导了其动刚度、滞后角和滞后角峰值频率的计算公式；利用数值计算法辨识了各集总参数；计算分析了液压衬套的动态特性；定性的分析了轴向型和径向型液压衬套集总参数模型中一些物理参数的变化对液压衬套动特性的影响。建立了双惯性通道式液压衬套的集总参数模型,分析结果表明惯性通道数目是优化液压衬套低频性能的重要参数之一。3.提出了一种不依赖实验样件制作的液压衬套集总参数的高效辨识方法。以径向型液压衬套为研究对象,基于其动力学特性分析的集总参数模型,应用ADINA有限元软件平台,采用双向耦合的液-固耦合非线性有限元分析方法辨识了集总参数模型中橡胶主簧的径向刚度、径向阻尼、液室的体积刚度、橡胶等效活塞面积以及惯性通道中液体的惯性系数和流量阻尼系数等关键物理参数。将有限元计算结果与数值拟合的结果进行相对误差对比分析,探讨了低成本前提下精确预测液压衬套集总参数模型的参数及动态特性的可行性。高效精确的参数识别方法不仅为后续液压衬套动力学性能分析奠定理论基础,同时也为液压衬套产品设计、性能优化和结构改进提供了必要依据。4·以径(?)型单惯性通道式和双惯性通道式液压衬套为研究对象,采用双向耦合的液-固耦合有限元分析技术计算了典型工况下液压衬套的静、动力学特性。采用液压衬套有限元模型,在低频大振幅激励和高频小振幅激励载荷下,计算分析了液压衬套液室和惯性通道中液体的压力分布情况,以及惯性通道中液体的速度分布特征,以深入了解液压衬套的减振机理,为液压衬套泄流方法的研究奠定了基础。更多还原

【Abstract】 Hydraulic bushing (HB) is a new kind of vibration isolator for automotive chassis system. It consists of fluid damping mechanism based on the structure of rubber bushing. The dynamic characteristics of hydraulic bushing greatly satisfy the vibration-isolation requirements of vehicle and improve the vehicle’s driving stability and riding comfort. Another advantage of hydraulic bushing is light and convenient installation. The domestic equipment manufactures have not mastered the design ability and the application of HB. The systematic research on the design theory and technology of hydraulic bushing is very necessary. For these purposes, the main research work is as follows:1. The static and dynamic characteristics of hydraulic bushing are thoroughly tested. The test method and data processing technique for mechanical properties of HB are discussed. The static stiffness of hydraulic bushings is compared with that of rubber bushing. The results show that the axial and radial static stiffness of hydraulic bushing are greater than that of the rubber bushing. The influences of excitation amplitude and frequency on the dynamic performances of hydraulic bushing are investigated.The stress-strain curves under different strain state are obtained based on the rubber material experiment. Three kinds of hyperelastic constitutive model used in FEM are analyzed. The least squares are applied to identify the constitutive model parameters. The constitutive model and model parameters with the minimum fitting errors are selected to describe the rubber material in FEA. This is the foundation for the further calculation of dynamic properties of hydraulic bushing.2. The lumped parameter (LP) models for axial and radial damping HB with single inertia track are proposed. The dynamic stiffness, loss angle and the peak frequency of hydro-bushing’s loss angle are obtained from the LP model. Emphasis is placed on the identification of the system parameters of the LP model for HB with single inertia track. The calculated dynamic performances of HB are compared favorably with the experimental data, which validates the proposed models. The influences of lumped parameters on the dynamic characteristics of HB are analyzed. The lumped parameter models for HB with double inertia tracks are established. With the increase of the number of inertia tracks, the peak frequency is backward moved. The analytical methods and conclusions are instructive for the design and the tuning of performance of the HB.3. An efficient identification method for lumped parameters is proposed, and does not depend on the experimental sample. Radial damping HB is the object, which is widely used as vibration isolator in the vehicle chassis system. Two-way fluid-structure interaction (FSI) nonlinear finite element analysis (FEA) technique is used to identify the main parameters of the LP model, such as the radial dynamic stiffness of the rubber spring, the radial damping of the rubber spring, the volumetric stiffness of the chamber, the equivalent piston area, the inertia and the resistance of the fluid in the inertia track. Comparing the calculated results with the numerical prediction results, the feasibility and accuracy of the FEA method was confirmed. The method proposed in this paper can ensure high quality and low cost in hydraulic bushing development.4. The two-way coupled FSI and FEA model for simulation of HB is developed, which can be used to simulate the static and dynamic performances of the HB with only stress versus strain relations of the rubber materials, the fluid physical parameters and the HB sizes. The dynamic fluid pressure and the velocity in the chambers and the inertia track of HB are calculated under different excitation conditions in order to deeply understand the damping mechanism.更多还原