一种改进的齿轮多体系统动力学模型

运用多体动力学理论建立了齿轮多体系统模型,该模型由可沿圆周转动的轮齿、弹性单元和齿轮本体组成,轮齿和齿轮本体虽然仍是刚体,但它们以转动弹簧-阻尼器相连接。采用了迟滞接触力模型分析轮齿间的啮合,为了验证该模型,分别以该模型、有限元模型和其他文献的模型研究单对渐开线直齿圆柱齿轮的啮合过程,对比分析表明:该模型的计算结果更接近于有限元方法,非常适用于齿轮系统的多体动力学分析。     

Dynamic analysis of three-dimensional helical geared rotor system with geometric eccentricity

A dynamic model of a multi-shaft helical geared rotor system is presented. Rotating shafts of the system are modeled as Timoshenko beams. A general three-dimensional dynamic model of helical gear pairs with geometric eccentricity is developed for the gear mesh and bearing flexibility is included in the model as well. The transmission error and gear geometric eccentricity are simulated as excitations. Eigenvalue solution and the modal summation technique are used to predict the natural frequencies and forced responses of the system. Then two geared rotor system models are presented for validation of the gear dynamic model. It is demonstrated that the gear mesh model is effective for general geared rotor systems, spur and helical gears, one-stage and multi-stage systems. Finally, forced responses of an example system are analyzed to demonstrate the influences of the helical gear geometric eccentricity and the coupling between gear geometric eccentricity and rotor mass unbalance.     

基于接触有限元的齿轮-转子系统动态特性分析

考虑齿轮-转子系统各部件的弹性,基于接触有限元理论提出一种能够高保真模拟齿轮副连续啮合过程的动态特性分析方法。该方法利用实体有限元进行系统建模,可体现各部件的结构特征;基于接触有限元进行啮合过程仿真,可模拟系统的时变刚度、啮合冲击等真实激励进而得到全面准确的响应信息。以一直齿轮-转子系统为例进行啮合过程的数值仿真,利用中心差分法求得系统各动力学参量在时域上的响应,通过中心距偏差、动态传递误差、动态接触力等参数分析系统的弯曲振动、扭转振动、齿轮副的啮合特性及其耦合关系。研究结果表明：考虑各部件尤其是转子的弹性后,系统的非线性振动特性显著,齿轮副啮合存在明显的双边冲击及脱啮现象。     

斜齿轮副动态特性对支承结构参数的灵敏度

针对斜齿轮副动特性的灵敏度问题 ,考虑轴和轴承的柔性以及由于轮齿啮合而产生的横向运动、扭转运动、轴向运动与旋转 (摆动 )运动间的动态耦合的影响 ,建立了斜齿轮传动系统的动力学模型 ,推导了固有频率及动态啮合挠度相对于斜齿轮副支承结构参数的灵敏度计算公式 ,并给出了实例。这一方法可用于斜齿轮传动系统的动态优化设计及改进设计     

钢/塑齿轮组合行星传动的振动特性

为了深入了解钢质行星齿轮传动系统引入塑料齿轮后的振动特性,建立钢/塑齿轮组合行星传动的动力学分析模型和试验模型,对SNS、SSS、SSN和NSS四种钢/塑齿轮组合行星传动的振动特性进行理论分析与试验研究,分析组合方式对行星传动振动特性的影响。数值仿真与试验研究结果表明:塑料齿轮的引入对行星齿轮传动的振动特性影响很大,显著地减小了太阳轮与行星轮和内齿圈与行星轮的啮合动载荷;有效地抑制了行星齿轮传动的齿轮啮合频带振动和高频带振动;组合方式对行星齿轮传动的振动特性影响显著,合理地采用钢/塑齿轮组合行星传动结构可以极大地降低啮合动载荷,从而有效地抑制传动系统的振动和噪声。     

单级齿轮传动系统有限元节点动力学模型及高速动态性能分析

研究用有限元节点建模方法建立考虑轴、齿轮转子陀螺效应的单级齿轮传动系统动力学模型,计算得到系统固有特性,与有限元软件和试验测量得到的结果进行对比,三种方法得到的系统固有频率具有一致性,验证有限元节点动力学模型有效性。由转子动力学稳定性理论计算得到系统的涡动临界转速等高速动态性能参数与响应特征,建立的齿轮轴系动力学模型为高速齿轮系统的设计及稳定性分析提供了基础参考。     

基于ADAMS多体动力学的轮齿动态载荷仿真分析

齿轮啮合过程中的轮齿动态载荷是齿轮研究领域的一个重要问题。文中介绍了直齿圆柱齿轮啮合传动特性以及ADAMS多体动力学分析中的接触碰撞模型;建立了基于ADAMS的直齿圆柱齿轮副多体动力学分析模型;通过动态仿真分析,获得齿轮啮合过程中的轮齿动态载荷历程,以及不同转速时轮齿的动载系数变化规律,为进一步研究直齿圆柱齿轮齿顶修形设计提供理论依据。     

含有柔性齿轮节点的多体系统动态模型

研究发展了通过将具有非线性柔性节点的多体系统离散为有限单元进行建模的方法。将连续元件的节点描述为特殊的节点单元，而非传统的非线性约束方程，节点单元可以方便地考察节点本身的柔性和元件之间复杂的时变接触。描述了非线性柔性铰接节点和齿轮节点单元的定义；建立了柔性多体系统的动力学模型，以实例展示了该方法的应用和分析精度。     

齿轮传动转子系统弯扭耦合振动研究

为分析齿轮传动复杂轴系的振动问题,根据有限元法和拉格朗日法,考虑陀螺效应、油膜支承等因素,得到了转子-轴承系统的弯扭耦合振动模型;在此基础上,根据齿轮副运动过程中啮合刚度和啮合阻尼的变化,得到了齿轮副系统的弯扭耦合振动模型。然后,根据齿轮副的实际排列方式,引入方位角,使得转子模型与齿轮副模型坐标统一化,并将其耦合到一起,得到了更加接近实际的齿轮转子模型,并且计算了其临界转速和振型。研究结果表明,耦合后转子的临界转速低于单转子的临界转速,齿轮传动对转子轴系振动有着明显影响。     

An efficient and accurate dynamic stress computation by flexible multibody dynamic system simulation and reanalysis

This paper presents an efficient and accurate method for dynamic stress computation based on reanalysis in flexible multibody dynamic system simulation. The mode acceleration concept that is widely used in linear strucural dynamics was utilized for accuracy improvement. A mode-acceleration equation for each flexible body is defined and the load term in the right hand side of the equation is represented as a combination of space-dependent and time-dependent terms so that efficient computations of dynamic stresses can be achieved. The load term is obtained from dynamic simulation of a flexible multibody system and a finite element method is used to compute stresses by quasi-static analyses. A numerical example of a flexible four-bar mechanism shows effectiveness of the proposed method for flexible multibody dynamic systems such as linkages and vehicle systems.     

带式啮合介质齿轮传动动力学性能分析

针对带式啮合介质齿轮传动中存在的动力学性能问题,首先建立了考虑齿轮啮合刚度、误差激励、介质带阻尼等参数的带式啮合介质齿轮传动系统简化振动模型,然后利用Solidworks软件对带式啮合介质齿轮传动系统进行了实体建模,最后导入ANSYS有限元分析软件对该模型进行了动力学性能分析仿真。研究结果表明：介质带的存在没有改变齿轮传动过程中的应力变化规律;带式啮合介质齿轮传动相比普通渐开线齿轮传动,其振动幅度减小,振动周期增大,介质带的存在改变了传动系统啮合刚度和啮合阻尼,起到了减振降噪的作用。     

2K-H行星传动系统动态可视化研究

以车辆行星齿轮传动系统为研究对象,基于多体动力学分析理论和齿轮系统动力学理论构建了行星传动系统的刚柔耦合多体动力学模型。分别针对车辆在理想稳态和实际档速复杂变化两种不同的运行工况下,研究该行星传动系统的动力学特性,得到关键部件在系统传动过程中的实时动态啮合力变化情况和数值仿真结果。仿真数据与理论分析吻合较好,仿真结果与实际相符,这为面向工程应用的齿轮系统优化设计、产品开发提供了技术手段。     

Research of design and analysis integrated information modeling framework for multibody mechanical system: with its application in the LHD design

Many complex mechanical products can be considered as multibody systems; 3D computer-aided design (CAD), multibody dynamics, finite element-based strength and fatigue analyses, optimization, and other CAE tools, are often used to develop this kind of product. But design is difficult and challenging because of information inconsistence among different engineering domains, and isolated information model islands exist. Lots of research are attracted to design and analysis information integration, but attentions are mainly focused on integration of CAD–finite element analysis (FEA), supporting the bottom-up design principle, while multibody dynamics analysis for analyzing global performance of a mechanical system is rarely considered, which follows the top-down design principle. In this paper, a novel multilevel system representation modeling framework for supporting both bottom-up and top-down or mixed design methods is proposed. It can integrate the product design CAD models with multibody dynamics, finite element-based strength and fatigue analyses, realizing a CAD–dynamic–FEA–fatigue analysis integration. It can also support data exchange and transfer in multidomain analyses. The framework is illustrated with a case study of a load haul dump (LHD) design using currently available software tools. Furthermore, a design case study of the working unit of the LHD is given to highlight the applicability of the modeling framework for multibody mechanical systems. It has been demonstrated that the framework can describe information exchanging and integration among CAD, FEA-based strength and fatigue analyses, and multibody dynamics analysis during a multibody mechanical product design process.     

Dynamic analysis of gear-rotor system with viscoelastic supports under residual shaft bow effect

This paper investigates the dynamic behaviors of a gear-rotor system with viscoelastic supports under effects of the gear eccentricity, the transmission error of gear mesh and the residual shaft bow. The investigated dynamic characteristics include system natural frequencies and steady-state response. The finite element method is used to model the system and Lagrangian approach is applied to derive the system equations of motion. The results show that the mass, the stiffness and the loss factor of the viscoelastic support will significantly affect system critical speeds and steady-state response. It needs larger loss factor and more rigid stiffness of the viscoelastic supports to suppress the systematic amplitude of resonance. As the results shown, the magnitude and phase angle of the residual bow have tremendous influence on first critical speed when the geared system mounted on stiff viscoelastic supports. The transmission error of the gear mesh is assumed to be sinusoidal with tooth passing frequency and it will induce multiple low resonant frequencies in the system response. It is observed that the excited critical speed equals to the original critical speed divided by gear tooth number.     

齿轮时变啮合刚度引起的分岔与动载荷

在考虑齿轮时变啮合刚度的情况下 ,建立了齿轮耦合的转子 -轴承系统的非线性动力学模型。用 Floquet理论分析了该系统的稳定性 ,结果发现 ,当转速超过某一临界值时 ,系统将产生 Hopf分岔 ;分岔将导致系统产生新的周期解 ;时变啮合刚度还将引起较大的动载荷 ,并导致脱齿现象发生     

柔性齿轮系统的多体动力学仿真研究

以渐开线齿轮为例,通过程序求得渐开线上的关键点,又在ANSYS中通过关键点创建齿轮渐开线,建立齿轮的有限元模型,导入到ADAMS中进行多体动力学仿真。通过ADAMS和ANSYS的结合,成功地实现了柔性齿轮系统动力学的仿真计算,使仿真结果更加贴合实际。实例表明,该柔性体仿真方法对包括齿轮机构存内的复杂机械系统的多体系统动力学仿真具有一定的参考意义。     

非惯性系平面多体机械系统键合图模型及其动力学原理

从能量守恒的基本原理出发，讨论了键合图中的多通口元件MTF所具有的性质。以此为基础阐述了建立非惯性系平面多体机械系统键合图模型的一般方法及其动力学原理。将运动副约束反力视做未知势源加在系统键合图模型相应的0—结处，有效地解决了微分因果关系及非线性结型结构所带来的十分困难的代数问题，实现了计算机自动建摸。实际算例表明了所述方法的有效性。     

Study on the dynamic model and simulation of a flexible mechanical arm considering its random parameters

Randomness exists in engineering Tolerance, assemble-error, environment temperature and wear make the parameters of a mechanical system uncertain So the behavior or response of the mechanical system is uncertain In this paper, the uncertain parameters are treated as random variables So if the probability distribution of a random parameter is known, the simulation of mechanical multibody dynamics can be made by Monte-Carlo method Thus multibody dynamics simulation results can be obtained in statistics A new concept called functional reliability is put forward in this paper, which can be defined as the probability of the dynamic parameters (such as position, orientation, velocity, acceleration etc) of the key parts of a mechanical multibody system belong to their tolerance values A flexible mechanical arm with random parameters is studied in this paper The length, width, thickness and density of the flexible arm are treated as random variables and Gaussian distribution is used with given mean and variance Computer code is developed based on the dynamic model and Monte-Carlo method to simulate the dynamic behavior of the flexible arm At the same time the end effector’s locating reliability is calculated with cncular tolerance area The theory and method presented in this paper are applicable on the dynamics modeling of general multibody systems     

基于图解-矩阵法行星齿轮传动系统运动学分析

对行星齿轮传动系统进行了基本单元划分,推导出基本运动单元的普遍速度和转矩方程,通过对速度和转矩方程的系数分析,建立了行星齿轮传动结构的图解模型以及方程系数与图解模型中参量的对应关系,提出了根据图解模型快速列出速度和转矩矩阵方程的图解分析法,为求解行星齿轮传动系统中各个运动学参量,提供了方便、快速、通用的方法。     

基于ANSYS直齿圆柱齿轮有限元模态分析

研究了直齿圆柱齿轮的固有振动特性，采用有限元法建立了直齿圆柱齿轮的动力学模型，通过有限元分析软件ANSYS对齿轮进行模态分析，得到了齿轮的低阶固有振动频率和主振型，可以为齿轮系统的动态设计提供参考，同时也为齿轮系统的动态响应计算和分析奠定了基础。