基于Payne效应的膜式空气弹簧非线性动刚度模型

本文中提出了一种考虑气囊橡胶Payne效应和热力学等效刚度阻尼滞回特性的膜式空气弹簧非线性动刚度模型,以解决空气弹簧动刚度非线性建模难题,并为气囊结构设计与材料选择提供理论依据。首先,通过示功试验对动刚度实部和虚部进行参数识别,表明在小振幅下,气囊橡胶Payne效应会引起动刚度的增大,并验证了不同振幅和频率激励下模型的正确性。接着,从振幅和频率两个维度给出了各解耦变量贡献度变化趋势的物理解释。结果显示,气囊橡胶的Payne效应使动刚度实部随振幅增大而减小,虚部随振幅增大呈现先增大后逐渐减小的趋势;气体刚度和由热交换产生的等效阻尼会使动刚度实部随频率升高逐渐增大,虚部随频率升高先增大后减小。最后给出了一个反映橡胶气囊动刚度贡献率的膜式空气弹簧新的评价指标,可直接表征空气弹簧低幅动态性能和结构设计与材料选择的优劣。试验表明,该值主要随振幅增加明显下降,橡胶气囊在低振幅时产生的刚度不可忽视。     

基于非线性空气弹簧模型的整车仿真与主客观评价

应用非线性空气弹簧模型,研究了空气悬架整车的动力学仿真和主观评价。结合空气弹簧频率、振幅相关性模型与Simulink仿真,给出了空气悬架整车7自由度模型,对比了不同路面情形下悬架动行程和簧上加速度的均方根值和功率谱密度。从时域和频率2个角度分析了不同速度、路面及减振器阻尼情形下空气悬架整车的动态特性。对装有不同空气弹簧的整车进行主、客观试验测试。结果表明：悬架动行程预测误差小于7%,簧上位置加速度共振峰值预测误差小于6%,共振频率预测误差小于6%;从而验证了所提模型的普适性和精确性;反映了带空气悬架整车的动态特性,解释了平顺性主客观试验的机理。     

大客车空气弹簧动态特性的试验分析

空气弹簧具有变刚度特性，其振动频率要比钢板弹簧低得多。对客车用空气簧动态特性进行了试验分析。结果表明，空气弹簧在多种载荷工况下特性曲线具有相似性，说明一种空气弹簧适合于多种载荷的汽车；空气弹簧的动刚度主要取决于激励频率，在低频范围内幅值比较小，高频范围内幅值比较大。     

有直动式液压间隙调节器的气门机构的动力学模型

针对有液压间隙调节器（ＨＬＡ）的气门机构，采用两种模拟ＨＬＡ的方法－弹簧阻尼模型和液压模型－构造了气门机构的动力学计算模型。ＨＬＡ的弹簧阻尼模型以串联在一起的弹簧和阻尼分别表示高压腔机油的可压缩性和泄漏的影响；液压模型则直接用流体力学导出的关系式计算高压腔机油压力，介绍了ＨＬＡ模型中主要刚度和阻尼尼系数的确定方法，以及一种估算ＨＬＡ高压腔机油混气比的新方法，关于气门机构和ＨＬＡ的试验以及动力学计算     

附加气室汽车空气悬架系统仿真及影响因素分析

附加气室空气悬架是通过在空气弹簧气室上增加一个气室,从而进一步降低空气弹簧刚度和提高阻尼的悬架。建立了附加气室空气悬架1/4二自由度系统动力学模型和数学模型,并对其进行了计算机仿真实验。通过观察仿真结果,分析了附加气室空气悬架对汽车行驶平顺性的影响因素。     

连接管路管径对空气弹簧动刚度特性的影响

对于带有附加气室的空气弹簧,主、附气室间连接管路的管径对弹簧刚度特性影响较大.用数值方法对管路内部气体流动进行模拟计算,采用FLUNET软件中模拟分析管路内部的三维流场,研究管径对管路内部流场和弹簧刚度特性的影响.同时,建立带附加气室空气弹簧特性试验系统,测试主附气室间连接管路不同管径时空气弹簧的动刚度特性.试验和模拟的结果表明,随着连接管路管径的增大,主附气室间气体交换量大,管路内部流场较稳定,弹簧动刚度减小.     

空气弹簧悬架系统在强迫振动下的动力学分析

利用非线性动力学的方法研究了空气弹簧悬架的非线性动力学特性。通过空气热力学方程和试验得出空气弹簧的刚度特性,对单自由度1/4车辆模型只考虑车辆的垂向运动,得到其振动方程,并研究在单频正弦激励情况下的主共振,利用平均法得到了一次近似解及幅频关系。利用奇异性理论分析其分岔集,可知系统为叉形分岔的普适开折。结果表明:激励幅值与非线性刚度是影响空气弹簧悬架非线性特性的主要因素,且非线性刚度中只有立方非线性起作用。     

独塔单索面斜拉桥动力特性分析与试验研究

独塔单索面预应力混凝土斜拉桥的动力特性有别于普通的大跨多塔斜拉桥,掌握其性能对研究其抗震性能与车振性能至关重要。通过某独塔单索面斜拉桥的现场脉动试验、跑车试验、跳车试验以及刹车试验等,测试了该桥的频率、振型、阻尼系数及冲击系数等动力参数。同时采用有限元分析方法建立了该桥的三维空间有限元模型,并进行了动力特性分析。对比结果显示,数值分析与实测吻合较好,该桥实际动刚度大于设计动刚度。     

金属弹簧电流变隔振器动特性试验研究

利用电流变液体（ERF）的可调阻尼特性,设计了一种金属弹簧电流变隔振器并阐述了它的工作原理,通过对简化力学模型的理论分析和隔振器试验研究,发现隔振系统的动特性对结构参数非常敏感,过高或过低的系统弹簧刚度均小利于发挥电流变效应。     

空气悬架大客车平顺性仿真研究

空气弹簧具有变刚度特性，其固有振动频率要比钢板弹簧低得多，且不随汽车承载质量的变化而改变。安装有空气悬架的汽车车轮动载荷小，可以获得良好的行驶平顺性、操纵稳定性和行驶安全性，减小了高速行驶车辆对路面的破坏。空气悬架在汽车悬架系统中的应用越来越广泛。本文以安装有空气悬架的大客车为研究对象，利用多体系统动力学原理建立空气弹簧大客车整车动力学仿真模型，并对其平顺性进行仿真研究。     

Development and analysis of an air spring model

The analytical model of an air spring can be effectively used for the design of air spring equipped vehicles to provide better ride and handling characteristics along with various functions for passenger convenience. However, establishing a general model of an air spring poses particular difficulties due to the severe nonlinearities in the stiffness and the hysteresis effects, which are hardly observed in conventional coil springs. The purpose of this study is to develop a general analytic model of an air spring — one which represents the main characteristics of stiffness and hysteresis and which can be connected to a model of pneumatic systems desigined to control air spring height. To this end, the mathematical model was established on the basis of thermodynamics with the assumptions that the thermodynamic parameters do not vary with the position inside the air spring, that the air has the ideal gas property, and that the kinetic and potential energies of the air are negligible. The analysis of the model has revealed that the stiffness is affected by the volume variation, the heat transfer, and the variation of the air mass and the effective area. However, the hysteresis is mainly affected by the heat transfer and the variation of the effective area. In particular, it was revealed that the increase of the volume due to the cross-sectional area increases the stiffness, while the increase of the volume due to the other reason decreases it. In addition, the model was used to develop the sufficient stability condition, and the stability of the model was analyzed. The paper also presents the comparison between the simulation and experimental results to validate the established model and demonstrates the potential of the model to be usefully employed for the development of the air spring and its algorithm for use in a pneumatic system.     

Study on dynamic characteristic analysis of air spring with auxiliary chamber

The characteristics of air springs, such as the effects of bellows and those of heat transfer on spring constant and damping factor, have been studied. However, auxiliary chambers and pipes are required in addition to air springs, to vary spring constant in the case of spring rate change by electronically controlled air suspension systems of a vehicle. Few reports have dealt with the effects of auxiliary chambers and pipes. In our study, the relation between vibration frequency and spring reaction has been investigated to clarify the effects of pipes on dynamic spring constant. Our proposed model has proved effective in understanding the phenomena.     

半主动悬架空气弹簧的动态特性研究

建立膜式空气弹簧的有限元模型,对其动态特性进行仿真和试验验证,仿真结果和试验结果吻合良好.研究表明,空气弹簧的输出频率是异频输出,且输出频率基本是激振频率的整倍数;随固有频率增加,空气弹簧变形加大.     

Model development and experimental research on an air spring with auxiliary reservoir

This paper focuses on the dynamic stiffness and overall equivalent damping of an air spring connected to an orifice and an auxiliary reservoir, with respect to the displacement excitation frequency, orifice area, and auxiliary reservoir volume. A theoretical model of this air spring with its auxiliary reservoir is derived by utilizing the energy conservation equation, gas state equation, and orifice flow rate equation. Simulation results from the presented model reveal that, when the air spring is subject to harmonic displacement excitation, its dynamic stiffness increases with an increase in excitation frequency and decrease in orifice area. Smaller orifice areas and lower excitation frequencies result in higher overall equivalent damping. A validation experiment is also implemented. When compared with experimental results, simulations show consistent varying trends of the dynamic stiffness and overall equivalent damping. The model developed here can correctly describe the behavior of the air spring with auxiliary reservoir, indicating that it is reasonable and feasible.     

金属主簧-复合材料副簧复合刚度计算模型

为了揭示金属主簧-复合材料副簧的变形机理并快速预测其复合刚度,综合应用板弹簧设计理论、复合材料层合板理论及有限差分法建立了金属主簧-复合材料副簧复合刚度的理论计算模型,并编写了相应的MATLAB计算程序。采用ABAQUS软件建立了某金属主簧-复合材料副簧总成的有限元模型并对其刚度特性进行有限元模拟。有限元模拟刚度与理论计算刚度之间的误差低于3%,从而验证了理论计算模型的正确性。建立的理论计算模型不但阐明了金属主簧-复合材料副簧的变形机理,而且适宜编程计算,能准确快速地预测金属主簧-复合材料副簧的复合刚度,这对复合材料板簧的推广应用具有重要意义。     

The Dynamics of a Railway Freight Wagon Wheelset With Dry Friction Damping

Summary We investigate the dynamics of a simple model of a wheelset that supports one end of a railway freight wagon by springs with linear characteristics and dry friction dampers. The wagon runs on an ideal, straight and level track with constant speed. The lateral dynamics in dependence on the speed is examined. We have included stick-slip and hysteresis in our model of the dry friction and assume that Coulomb's law holds during the slip phase. It is found that the action of dry friction completely changes the bifurcation diagram, and that the longitudinal component of the dry friction damping forces destabilizes the wagon.     

汽车发动机液阻悬置动特性仿真与实验分析

本文总结了发动机悬置系统的隔振要求和常用的悬置元件动特性评价参数，指出了悬置元件为满足高、低频隔振要求而产生的设计上的矛盾和困难。通过激振实验方法测试了液阻悬置元件及其橡胶主簧的动刚度和阻尼特性。对一种轿车动力总成液阻悬置建立了集总参数的力学和数学模型，进行了动特性仿真，并与实验测试结果进行了对比分析，表明该模型对液阻悬置的低频动特性分析很有效，在高频段也可以预测液阻悬置开始发生动态硬化的频率，对于液阻悬置产品的设计和改进具有指导意义。     

Effect of Connecting the Front and Rear Air Suspensions of a Vehicle on the Transmissibility of Road Undulation Inputs

Airsprings have been used for vehicle suspensions over the last 40 years. They are mostly used as independent suspensions. Analysis of air springs available in literature is mostly limited to a single-degree-of-freedom system or a two-degrees-of-freedom system only in the translation mode. This paper deals with a model of a vehicle where the front and the rear springs are connected by a capillary tube. A two-degrees-of-freedom model having motion in bounce and pitch mode is presented. Equations of mass flow are linearized on the assumption of small variations in volume and pressure. Expressions for the transmissibility and the phase angle in the bounce and the pitch mode are derived. Road inputs to the front and the rear axles are assumed to be identical except for a phase difference between them. The effect of the capillary flow coefficient and that of the phase angle between the front and the rear axle excitation are studied. It is shown that an optimum value of the capillary flow coefficient exists which minimizes the transmissibility of motion in both modes over the entire frequency range. It is also observed that a phase angle of 180 degrees presents ideal transmissibility characteristics. Thus, a promising application of air springs for a vehicle suspension is presented.     

Effect of Connecting the Front and Rear Air Suspensions of a Vehicle on the Transmissibility of Road Undulation Inputs

SUMMARY

Airsprings have been used for vehicle suspensions over the last 40 years. They are mostly used as independent suspensions. Analysis of air springs available in literature is mostly limited to a single-degree-of-freedom system or a two-degrees-of-freedom system only in the translation mode. This paper deals with a model of a vehicle where the front and the rear springs are connected by a capillary tube. A two-degrees-of-freedom model having motion in bounce and pitch mode is presented. Equations of mass flow are linearized on the assumption of small variations in volume and pressure. Expressions for the transmissibility and the phase angle in the bounce and the pitch mode are derived. Road inputs to the front and the rear axles are assumed to be identical except for a phase difference between them. The effect of the capillary flow coefficient and that of the phase angle between the front and the rear axle excitation are studied. It is shown that an optimum value of the capillary flow coefficient exists which minimizes the transmissibility of motion in both modes over the entire frequency range. It is also observed that a phase angle of 180 degrees presents ideal transmissibility characteristics. Thus, a promising application of air springs for a vehicle suspension is presented.