风电齿轮传动系统弹流润滑特性研究

为研究风电机组齿轮传动系统的润滑特性和动力学特性,以SQI风电机组传动系统实验平台中两级定轴齿轮箱为研究对象,综合考虑齿轮油膜刚度、齿轮啮合刚度以及轴承时变刚度等,计入轴的柔性并采用有限元法建立多自由度渐开线直齿轮动力学模型,利用Newmark 积分方法求解多源时变激励下两级齿轮传动系统的动力学特性。讨论不同工况条件对油膜刚度的影响,并研究系统润滑特性、固有频率和振型的变化规律。研究结果表明,在考虑齿轮润滑效应后,齿轮啮合刚度降低,系统动态特性变化趋于敏感,系统固有特性均有所变化,其中对第11阶影响最为突出,然而在系统共振转速附近,固有特性变化趋势有所减弱。     

齿根裂纹对风电齿轮箱高速级动态特性影响分析及其故障模式识别

针对风电齿轮箱高速级齿轮传动系统齿根裂纹扩展程度识别难题,该文提出基于广义BP神经网络（GBPNN）的齿轮传动系统齿根裂纹故障模式识别方法。构建计及齿根裂纹扩展方向与路径的齿轮副时变啮合刚度解析模型及风电齿轮箱高速级齿轮-轴-轴承耦合的多自由度动力学模型,分析不同齿根裂纹扩展程度对系统振动特征的影响规律,并利用GBPNN对齿根裂纹故障模式进行识别。研究结果表明：齿轮故障振动周期冲击信号将沿着传动轴进行传递,但传动轴柔性会使其幅值产生明显的衰减;利用GBPNN并结合各轴段节点处振动加速度的峰值、峭度、统计矩阵参数以及方差,可有效实现对齿轮齿根裂纹故障模式的识别。     

风电齿轮箱高速轴轴承疲劳寿命及动态可靠性分析

为探究风电机组齿轮箱高速轴圆柱滚子轴承在服役过程中的疲劳寿命和可靠度变化规律,以新疆达坂城风场年度风载荷为外部激励,建立基于威布尔分布的随机风速模型及考虑内部齿轮时变啮合刚度、轴承时变刚度等激励因素的风电齿轮传动系统齿轮-轴承耦合动力学模型,通过Newmark积分法求解高速轴轴承动载荷。运用雨流计数法及Goodman平均应力修正法得到对称循环应力,结合线性损伤理论和非线性损伤理论的对比,获得轴承的接触疲劳寿命和动态可靠度。结果表明：额定功率下,在外部随机风载激励和内部齿轮-轴承耦合共同作用下,内激励仍然对系统高速轴轴承动载荷起主要作用。与线性损伤累计理论相比,非线性损伤累计理论考虑载荷加载的顺序效应,能更好地描述轴承在整个疲劳寿命过程中各阶段的疲劳损伤情况。轴承在服役过程中,前15年的损伤较小,可靠度衰减缓慢,而在后期可靠度呈现出非线性迅速下降趋势,应及时调整维护策略。     

功率六分支同轴人字齿轮传动系统动态特性与均载特性研究

功率六分支同轴人字齿轮传动是某船舶动力传输系统的重要组成部分,为了对船舶动力系统的振动噪声和动态载荷进行评估,需要开展功率六分支同轴人字齿轮传动系统的动态特性与均载特性研究。本文采用集中参数法建立了含时变啮合刚度和传动误差的扭转振动模型,并采用解析法求解动力学方程;依据齿轮副沿啮合线的相对振动响应,给出了动载系数与均载系数计算公式;分析了输入轴、双联齿轮轴及输出轴的扭转刚度对传动系统动载特性和均载特性的影响。结果表明：输入轴扭转刚度对系统均载特性影响较大;双联齿轮轴扭转刚度对分扭级和并车级的均载特性均有影响,且随着双联轴扭转刚度增加,动载系数均变大;输出轴扭转刚度对传动系统各分支动载系数几乎没有影响。     

大型风力发电机齿轮箱全柔体动力学建模与仿真分析

以SIMPACK多体动力学仿真软件为仿真平台,结合ANSYS有限元分析软件和GH Bladed载荷计算软件在充分考虑各零部件的柔性、齿轮啮合的时变刚度及轴承刚度等因素的条件下建立某型号风电齿轮箱的箱体-传动轴-齿轮的全柔性体模型,并对整个系统进行动力学仿真研究,得到系统的固有频率、各频率下的能量分布图、速度加速度等振动信号,提供一种风电齿轮箱建模新方法并为齿轮箱动态特性优化设计提供了依据。     

双馈式风电机组传动系统动态特性研究

针对双馈式风电机组柔性传动系统运行稳定性问题,采用集中参数质量法建立风电机组柔性传动模型,在考虑外部风载、齿轮副啮合刚度、啮合阻尼和综合啮合误差激励条件下,建立了齿轮箱内部各级齿轮副动力学方程;以市场成熟的1.5MW双馈式风电机组为计算对象,计算了柔性传动系统固有频率和齿轮箱各级齿轮动态啮合力;通过雨流计数法对齿轮动态啮合力进行数据分析,研究了传动系统运行稳定性。研究结果表明,齿轮副啮合力呈现高频波动,具有很强的时变特性,通过雨流计数分析,动态啮合力幅值与频次成正态分布规律;传动系统一阶扭转振动频率与风轮面内一阶摆阵频率偏差为6.8%,通过降低主轴质量约9.5%,提高了传动系统一阶扭转频率约11.5%,与风轮面内一阶摆阵频率偏差达16.4%。研究结果可为风电机组传动系统设计、轴承寿命计算和可靠性研究提供参考。     

随机风载作用下风力发电机齿轮传动系统疲劳寿命预测

针对风电齿轮传动系统在复杂随机风载下运行的特点,运用加权最小二乘支持向量机(Weight Sparse Least Squares Support Vector Machines,SLS-SVM)方法建立风场随机风速模型,进而得到随机风引起的系统外部载荷激励。建立考虑齿轮时变啮合刚度、综合啮合误差、滚动轴承变刚度的风电齿轮传动系统的平移-扭转动力学模型,求得传动系统各齿轮副的动态啮合力和各支承轴承的动态接触力及相应的应力时间历程。应用雨流计数法统计循环参量,结合Goodman公式将工作循环应力水平按等寿命原则转换为对称循环下的疲劳应力谱。基于Palmgren-Miner线性累积损伤法则和材料P-S-N(失效概率-应力-循环次数)曲线,预测风电齿轮传动系统各齿轮和轴承的疲劳寿命。为风力发电机齿轮传动系统动态疲劳寿命预测提供了理论方法。     

风电增速箱行星传动系统动力学方程及均载特性

提出一种风电增速箱用新型载荷分流式两级行星齿轮传动机构,以便提高传动系统的承载能力。以新型风电增速箱载荷分流型两级行星轮系与一级平行轴齿轮构成的多级传动系统为研究对象,计入多级耦合传动系统的轮齿啮合误差、啮合阻尼、啮合刚度,级间扭耦合刚度,组件的转动惯量等影响因素,采用集中参数法建立多级耦合传动系统的动力学模型。利用相关参数对系统的均载特性进行研究,获得行星齿轮传动的均载系数曲线。分析表明:各级内外啮合的均载系数均随时间变化且存在相位差;第一级内外啮合的均载系数分别比第二级内外啮合的均载系数分配均匀;第一级均载系数较小且内外啮合的均载系数的差别较小。     

考虑齿轮接触状态影响的热气机振动响应计算

为了研究不同齿轮接触力计算方法对热气机振动响应计算的影响，用多体动力学软件建立其传动系统的刚柔混合多体动力学模型，并通过模态分析验证缩减模型的正确性。分别使用Weber-Banaschek法以及有限元缩减模型的柔性齿轮有限元法进行齿轮时变啮合刚度计算，将不同齿轮时变啮合刚度的热气机整机机脚振动计算值与实测值进行对比，结果表明：采用Weber-Banaschek法计算得到的齿轮啮合刚度误差较大（13.5%）；采用有限元缩减模型的柔性齿轮有限元法计算得到的齿轮啮合刚度误差较小（2.1%），其与理论值更接近。     

制动工况下风电齿轮传动系统的动力学特性分析

考虑多种内、外部因素通过仿真获得风力发电机正常制动时齿轮箱的外部载荷。采用集中质量参数法在考虑齿轮时变啮合刚度、啮合阻尼、综合啮合误差、齿侧间隙和齿面滑动摩擦力等因素的情况下建立风力发电机齿轮传动系统的纯扭转非线性动力学模型;利用数值方法求得传动系统在制动工况下各齿轮副沿啮合线的振动位移和动态啮合力等;分析齿侧间隙和齿面滑动摩擦力对风电齿轮传动系统动力学的影响。     

大型风力机齿轮传动系统机电耦合动态特性研究

针对目前风力机柔性齿轮箱动力学研究时简化电气系统的问题,以某8 MW永磁同步风力机为对象,建立包含详细电气系统和柔性传动链的风力机模型。基于该模型探究电气系统效应对风力机齿轮箱啮合刚度、动态接触应力、振动加速度等动力学特性影响。结果表明：电气系统效应使系统转速、时变啮合刚度、接触应力相位滞后且波动减小;电气系统效应抑制各级齿轮角加速度及箱体振动加速度高频成分并减小传动链振动;风速突变时,电气系统效应可减小高速级齿轮峰值啮合力,增强风力机传动链抵御冲击能力。     

变风载下风力发电机齿轮传动系统动力学特性研究

根据风力发电机齿轮传动系统所处的由随机风速引起的复杂变工况环境,用自回归AR风速模型模拟实际风场的风速,获得了由随机风速引起的时变风载荷;采用集中质量参数法建立了传动系统的纯扭转动力学模型,求得了系统的固有频率和阵型;研究了传动系统在时变风载下的动态特性,求得了各齿轮的振动位移和各齿轮副的动态啮合力,为风力发电机传动系统的动态性能优化和可靠性设计奠定了基础。     

基于齿廓修形和摩擦耦合的风电齿轮磨损动力学特性分析

为定量研究齿面磨损（TSW）的振动特性,提出一种基于齿廓修形和摩擦耦合的磨损故障建模方法,并引入最大磨损深度来表征齿面磨损程度。以大型风电机组齿轮箱高速输出轴直齿轮为研究对象,得到对应不同磨损程度下的齿轮时变啮合刚度,并将其代入到齿轮箱8自由度动力学微分方程,在不同转矩条件下对齿轮箱进行动力学仿真,得到不同磨损严重程度和转矩条件下的振动时频域特性。结果表明：仿真结果与实验数据吻合良好,验证了该方法的有效性;随着齿面磨损程度增加、转矩增大,齿轮箱振动、齿轮扭振剧烈;在0.4倍额定转矩附近,齿面磨损引起齿轮箱振动速度、振动加速度最为明显。研究结果可为齿轮磨损故障诊断提供理论指导。     

750 kW风力机组齿轮箱动力学仿真分析

风力发电机组系统运行时产生剧烈的振动,对齿轮箱的运行精度和齿轮寿命的影响非常大。针对这一情况,文章对齿轮箱进行了重新设计、建模。基于多体系统动力学方法、模态振动、冲击-接触理论,以750 kW型风机齿轮箱为研究对象,通过对齿轮箱的仿真分析,得出齿轮啮合和碰撞力以及动能随时间的变化曲线。文章还对高速齿轮轴进行了模态分析,得到弯曲模态振型图,并将高速齿轮轴、行星轮、行星架和齿轮Z1变为柔体进行应力分析,得到齿轮的应力分布图,为齿轮箱总体动力学特性分析及齿轮箱优化设计奠定基础。     

Dynamic response analysis on torsional vibrations of wind turbine geared transmission system with uncertainty

Gearbox transmission system is the major part of the wind turbine drive train. Due to the manufacturing and assembling errors, lubrication condition, wear and uncertainties in material and geometric properties, the system parameters, including mesh stiffness, transmission error and damping of the meshing gears are always uncertain. For a more reasonable evaluation of dynamic characteristics of the gearbox transmission system, the influence of the uncertain parameters should be taken into consideration. Based on the Chebyshev interval method (CIM), the dynamic responses of a geared transmission system with uncertain parameters are thus investigated in this paper. A torsional vibration model is derived for a geared system, in which some parameters including the mesh stiffness, the transmission error, the mesh damping, the shaft damping, the moment of inertia of the input blades and the torsional stiffness of the driving coupling shaft are considered as uncertain but bounded parameters. Interval dynamic equations of the geared system are solved by use of the CIM in combination with the variable-step Runge-Kutta numerical integration method. The accuracy of the CIM is demonstrated in comparison with the Monte Carlo (MC) simulation. Variations of the upper and lower bounds of the dynamic mesh force with input speed are obtained. The effects of those uncertain parameters on the frequency response of the dynamic mesh force are discussed in detail. It is shown that small parameter uncertainties might be propagated in the vibration system and lead to relatively large uncertainties of the dynamic response of system. The result is of significance for the design and condition monitoring of wind turbine drive trains.     

Using transfer path analysis to assess the influence of bearings on structural vibrations of a wind turbine gearbox

Noise and vibration issues can be dealt with using several approaches. Using the source–transfer path–receiver approach, a vibration issue could be solved by attenuating the source, modifying the transfer path or by influencing the receiver. Applying this approach on a wind turbine gearbox would respectively correspond with lowering the gear excitation levels, modifying the gearbox housing or by trying to isolate the gearbox from the rest of the wind turbine. This paper uses a combination of multi‐body modelling and typical transfer path analysis (TPA) to investigate the impact of bearings on the total transfer path and the resulting vibration levels. Structural vibrations are calculated using a flexible multi‐body model of a three‐stage wind turbine gearbox. Because the high‐speed mesh is often the main source of vibrations, focus is put on the four bearings of this gear stage. The TPA method using structural vibration simulation results shows which bearing position is responsible for transmitting the highest excitation levels from the gears to the gearbox housing structure. Influences of bearing stiffness values and bearing damping values on the resulting vibration levels are investigated by means of a parameter sensitivity study and are confirmed with the results from the TPA. Because both the TPA and the parameter sensitivity analysis revealed a big influence on radial stiffness for a certain bearing, this was investigated in more detail and showed the big importance of correct axial bearing position. The main conclusions of this paper are that the total vibration behaviour of a wind turbine gearbox can be altered significantly by changing both bearing properties such as stiffness, damping and position, and bearing support stiffness. Copyright © 2014 John Wiley & Sons, Ltd.     

Fault diagnosis of wind turbine planetary gearbox under nonstationary conditions via adaptive optimal kernel time–frequency analysis

Planetary gearboxes play an important role in wind turbine (WT) drivetrains. WTs usually work under time-varying running conditions due to the volatile wind conditions. The planetary gearbox vibration signals in such an environment are hence highly nonstationary. Conventional spectral analysis and demodulation analysis methods are unable to identify the characteristic frequency of gear fault from such nonstationary signals. As such, this paper presents a time–frequency analysis methods to reveal the constituent frequency components of nonstationary signals and their time-varying features for WT planetary gearbox monitoring. More specifically, we exploit the adaptive optimal kernel (AOK) method for this challenging application because of its fine time–frequency resolution and cross-term free nature, as demonstrated by our simulation analysis. In this study, the AOK method has been applied to identify the time-varying characteristic frequencies of gear fault or to extract different levels of impulses induced by gear faults from lab WT experimental signals and in-situ WT signals under time-varying running conditions. We have demonstrated that the AOK is effective diagnosis of: (a) both the local damage (a single chipped tooth) and distributed faults (wear of all teeth), (b) both sun gear and planet gear faults, and (c) faults with very weak signature (e.g., the sun gear fault at the low speed stage of a WT planetary gearbox).     

Load sharing behavior analysis method of wind turbine gearbox in consideration of multiple-errors

Conducting a further analysis on loading sharing among compound planetary gear system in wind turbine gearbox, and making a meshing error analysis on the eccentricity error, gear thickness error, base pitch error, assembly error, and bearing error of wind turbine gearbox respectively. In view of the floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of all gears, this paper establishes a refined mathematical model of two-stage power split loading sharing coefficient calculation in consideration of multiple errors. Also obtains the regular curves of the load sharing coefficient and floating orbits of center gears, and conducts a load sharing coefficient test experiment of compound planetary gear system to verify the research results, which can provide scientific theory evidence for proper tolerance distribution and control in design and process.