风电齿轮箱传动误差分析及振动噪声预估

针对一级行星两级平行轴风电齿轮传动系统,综合考虑齿轮时变啮合刚度、啮合阻尼、传递误差等因素,建立31个自由度的弯扭轴耦合集中参数动力学模型,采用变步长Runge-Kutta法对系统动力学微分方程进行求解,得出齿轮传动系统各级传动误差;借助软件建立风电齿轮箱刚柔耦合动力学模型,并导入传动误差,采用模态叠加法求得齿轮箱轴承支反力,并将其作为声振耦合模型的边界条件,采用声学有限元法对风电齿轮箱进行振动噪声预估,并与试验结果对比分析,两者吻合良好。     

风电增速齿轮箱动力学性能优化方法

建立增速齿轮箱动力学分析有限元模型,利用Lanczos法求得齿轮系统的振动模态;以齿轮副时变啮合刚度激励、齿面综合误差激励和轮齿啮合冲击激励为内部作用激励,采用直接积分法求得箱体表面节点的动态响应。选取箱体上12个主要结构参数作为动力学性能优化的设计变量,齿轮箱体积为状态变量,以齿轮箱表面振动加速度的均方根值最小为动力学性能优化的目标函数,利用零阶与一阶优化算法求得最优设计变量。结果表明：优化前后箱体均不产生共振,且满足静力学条件;优化后目标函数减小37.5%,箱体各计算点的振动响应均有较大幅度的减小,最大减小量为54%。     

Dynamic analysis of wind turbine gearbox

By inputting reduced matrix of stiffness and mass, a dynamic model including flexible housing, ring gear and carrier for a 3 MW wind turbine gearbox is established based on MASTA. And analysis results show that the kinetic percentage of housing is maximum near the gear mesh frequency and response is maximum at the 1st mesh frequency of HSS gear. The analysis results show certain agreement with vibration test results. This paper can provide reference for avoiding vibration in gearbox design.     

Fatigue life finite element analysis of output gear pair of wind turbine speed-increase gearbox

Cracking monitoring provides an important way to evaluate structural safety. Cracking monitoring method based on distributed optical fiber sensor can effectively avoid undetected phenomenon existed in point-wise test method, and it can run automatically. A theoretical model of cracking monitoring based on obliquely intersected fibers and Brillouin Optical Time Domain Analysis (BOTDA) is introduced, and the numerical equation among fiber strain, crack width and crack angle is established by the calibration experiment. The experiments are also carried out to study the performance of different kinds of cracking sensors with different gauge length and pretension. The quantitative relationship between optical fiber measured strain and crack (including width and angle) is established for the 300 millimeter crack sensor. The cracking simulation test proved that this new method can effectively record the width and the angle of cracks during the whole cracking process.     

Analysis and test on vibration and acousticnoise of GWC6066 marine gearbox

The mesh stiffness of gear tooth is simulated by spring elements, the connected bolt between various housings are simplified as bar elements, and the sliding bearing and rolling bearing are simplified as spring dumping elements. Based on them, the gear-shaft-bearing-housing coupled finite element model and boundary element model of GWC6066 marine gearbox are established. Finally, the dynamic response under internal dynamic excitation is analyzed and the vibration severity, structural-borne noise and air-borne noise of the gear system are forecasted. Through the experimental modal analysis of gear system, and the test of vibration response and air pressure, the natural frequencies, vibration severity, structural-borne noise and air-borne noise are obtained. Compared with numerical results, two results show good agreement.     

Approaches to enhance power density of gearboxes for wind turbines

Based on pitting strength, some approaches to enhance power density of gearboxes for wind turbines are discussed. The calculation load is greatly reduced by power division. Allowable stress numbers are effectively increased by improving property of quality materials, precision heat treatment or shot peening. Load capacities can be also obviously enhanced by improving the tooth shape of morphology optimization of tooth root, tooth correction or superfinishing of tooth surface. The center distance is effectively decreased by minishing minimum allowable safety factor or enlarging face width. The power density of gearbox can be further improved by means of structure optimization of planet carrier or uniform load of planetary gear transmission.     

ANSYS/PDS风电齿轮箱收缩盘联接可靠性分析

笔者建立了某风电齿轮箱主轴收缩盘联接的轴对称参数化有限元模型,并结合主轴扭矩作用应用ANSYS非线性接触对该模型进行了强度分析。由于材料属性、制造过程、边界条件以及载荷等设计参数的不确定性会影响计算的精确性,应用ANSYS/PDS模块,根据失效模式确定整体功能函数并由此建立结构极限状态方程,采用蒙特卡罗超拉丁采样方法对收缩盘联接进行可靠性分析,得到整体联接的可靠度和失效率,并给出累积概率分布。研究结果表明:收缩盘传扭联接性能和结构件强度均满足设计要求,其联接的可靠度达到94.8%,达到了工程设计要求,对风电齿轮箱收缩盘联接的可靠性设计具有一定的指导意义。     

Numerical simulation of dynamic response and radiation noise of gearbox

Considering the internal dynamic excitation produced by stiffness excitation, error excitation and mesh impact excitation, a dynamic finite element model of transmission system and structure system of gearbox is established. The normal mode and the dynamic responses of gearbox under the internal dynamic excitation are calculated by using the numerical simulation software ANSYS. Based on the result of dynamic responses, the boundary excitation condition is determined, and then the acoustic boundary element model is built. With the software of SYSNOISE, the surface acoustic pressure of gearbox and the radiation noise of field points are solved by the direct boundary element method. The test of airborne noise is carried out. The computational results obtained are in a good agreement with the data of experimental test.     

Analysis of gear micropitting for megawatt-class wind turbine gearbox

Gear micropitting phenomenon is common in megawatt-class wind turbine gearbox because of the hard operating environment and complicated load case. More and more attention has been paid to it during recent years. Main factors influencing gear micropitting, such as surface roughness, modification coefficient, oil temperature, are discussed in this paper according to ISO/TR 15144—1:2010. Reasonable values for the factors are suggested and software for calculating micropitting is developed. Based on observation and discussion, measures for reducing gear micropitting risk in wind turbine gearbox design are proposed.     

The analysis of China wind power industry

The development course of China wind power industry is reviewed by six stages. National policies on wind power industry are elaborated from the aspects of laws & regulations, planning, finance & taxation and electrovalence policy. And these policies have played an important supporting and regulating role in the development of wind power industry. The development status of China wind power industry is analyzed based on wind turbine installed capacity, wind power output and their growth rate. It is explained that national wind turbine manufacturers have kept developing and become strong by the data of new global installed capacity share of mainland wind turbine manufacturers in 2013 and the new global market share of 8 domestic enterprises among the world top 15 wind turbine manufacturers. But there are still 5 key problems which influence the development of national wind turbine need to be solved, including lack of top-level design, abandon and restriction wind power seriously, lack of R&D abilities, some of the key parts relying on imports and wind turbine facing a quality guarantee dilemma. Taking Sinovel Wind Group Co. Ltd. and Xinjiang Goldwind Sci & Tech Co. Ltd., the two leading companies as an example, their performance is analyzed and it’s pointed out that the wind industry must keep vigilant after the overspeed development. The enterprises should try to avoid neglecting cultivating their inner core competitive ability, including technology advancements and products reliability. Occupying the market with low price competition and expanding blindly is also not desirable. At last, the development prospects of our country’s wind power industry are analyzed and three proposals are put forward.     

structural optimization of high power marine gearbox

Taking the influences of joggle forces and gravity into account, a static model of a high power marine gearbox was established using the finite element method. The gearbox workload capacity was calculated in four working states. Gearbox strength and structural rigidity were analyzed. Combining theories of optimization and reliability design, the gearbox optimization model was obtained based on the intensity principle. To insure a safe structure, optimization designs were put in practice to improve the gearbox structure. As a result, the gearbox weight was reduced 1 060 t by structural optimization. The strength of the improved gearbox is more symmetrical and the structure of the improved gearbox is more reasonable than previoius designs, indicating the method has certain theoretical and practical engineering values.     

Research and developments of manufacturing technology onwind turbine gearbox

The manufacturing quality and technology of gearbox, which is a core component, is the key guarantee for the superior performance of wind turbine. Wind turbine gearbox manufacturing is a comprehensiveness technique involved multiple disciplines. To realize the digital lean manufacturing, the in-depth research on the fundamental process theory and the process control method should be carried out by taking full advantage of the existing techniques. Also, some new technologies, new processes and new materials should be investigated and applied. By considering the structural features and the actual operational condition for wind turbine gearbox and combining production practices, the requirements and characteristics of the process techniques are summarized. The research state, existing problems, applications and development tendency of high-performance wind turbine gear manufacturing, housing manufacturing and planet carrier manufacturing are analyzed. Then some methods are proposed to improve the manufacturing efficiency and control the heat treatment deformation. Finally, the test techniques for wind turbine are introduced. It has project practical significance for the manufacturing of wind turbine gearboxes.     

切割片减振降噪的优化设计

为了研究切割片在工作过程中的振动及噪声问题,基于有限元方法,借助于ANSYS APDL有限元软件建立了切割片有限元模型;采用反转法施加载荷,简化模型及分析过程,在振动特性分析中,得出调整切割片结构参数可以降低切割片振动幅度的结论;基于振动能量与速度的平方关系,以测试点的速度平方和为目标函数,设计了优化程序对切割片模型进行调整优化,获得了一组最优调整数据,为实际生产提供了参考依据。     

Numerical analysis of noise radiation from motorcycle engine shell

FEM/BEM (Finite Element Method/Boundary Element Method) mode analysis of the noise radiation from motorcycle engine shell is conducted. The natural frequency is compared between FEM/BEM analysis and experimental analysis. The FEM/BEM results are agreed with the experiment results, which proves that the finite element model is correct. The frequency response is analyzed and the structure’s noise radiation is simulated by means of FEM/BEM, in order to predict the noise radiation from the motorcycle engine shell and gain the sound field characteristic outside the structure. The calculation data is compared with the experiment data in different frequency bands. The result shows high accordance, which indicates that this method is effective.     

Experimental study on vibration and structure noise of marine gear box with heavy load

The performance requirements of marine gear box are much higher than that of other gear boxes due to its special working conditions. The structure and transmission principle of a high-power marine gearbox are analyzed, and the experimental test is carried out for the analysis and calculation of its vibration characteristics and intensity. Measured by FFT analysis of vibration signals, the main peak is caused by its octave and the engagement frequency of input stage and middle-class transmission. The vibration severity of high-power marine gearbox reached 4.47 mm/s. In addition, the calculated structure noise of the measuring points is at the 1/3 octaves, and the largest structure noise is 131.27 dB which occurred in the frequency of 329 Hz.     

CVT刚性联接发动机曲轴轴系结构的扭振分析

因非道路车辆的特殊结构和成本限制,提出四缸柴油发动机中采用CVT刚性联接曲轴轴系结构。阐述了该新型结构的特征和工作原理,建立了四缸柴油发动机离合式曲轴计算模型和CVT刚性联接曲轴计算模型。通过曲轴前端实验,证明了所建模型和模型参数确定方法的正确性。求解所有计算模型,并对结果进行对比分析。结果表明,CVT刚性联接使曲轴轴系振动波动加大,减振器耗散能增加,各阶共振峰值对应转速低减。对曲轴各拐剪切应力幅度的影响不大,但有高转速工况降低而中低转速剪切应力幅值增加的普遍趋势,CVT端的扭振振幅和剪切应力较大些。综合研究得出结论：非道路车辆低速四缸柴油发动机可以采纳CVT刚性联接曲轴轴系结构。     

Modeling and simulation of a grid connected wind turbine withdoubly fed induction generator

In order to fully research the effects of external excitations, such as wind speed, wind direction and voltage disturbance, on a grid connected wind turbine with doubly fed induction generator, a co-simulation model of MW-class wind turbine system is established by using Simpack and Matlab/Simulink software. Also, by considering the actual control strategies in the process of simulation, the relationship between external excitations and mechanical system is studied. According to time-domain simulation under the turbulent wind condition, the dynamic meshing forces of gears are analyzed. Besides, the vibration responses of tower are calculated under the different external excitations. Research results lay a foundation for dynamic performance optimization and reliability design of a wind turbine.     

A calculation method of the stiffness of face gear tooth and analysis of its influence factors

Tooth stiffness of face gear is one of the components of meshing stiffness of face gear drives. Its resolve can build excellent base for calculation method of meshing stiffness and analysis of dynamic for face gear drives. Based on Buckingham’s standpoint, along the length direction of the tooth of face gear, any one of its sections can be considered as a section of rack with varying pressure angle. According to above theory, the tooth form of face gear is simulated successfully. The method of calculation of the tooth’s stiffness of face gear is obtained. Compared with conclusion of tooth’s stiffness by FEM in the same parameters, it is proofed to be correct. Through analysis of influence of tooth’s stiffness by main design parameters of face gear, the benefit conclusions are drawn. That is, the changing ratio of tooth’s stiffness decreases with the increase of module, and the tooth’s stiffness increases with the increase of pressure angle but the changing ratio almost remains constant. The tooth’s stiffness increases with the increase of tooth width and the influence of changing ratio from tooth root to tooth crest is bigger than that of pressure angle.     

Dynamic characteristics analysis of megawatt wind turbine drive train

Since the wind turbines are installed on the flexible support tower, the drive train of the wind turbines runs under severe work conditions with varying wind directions and loads. So its failure rate is high and it is the bottle neck of the wind power development. This work presents a study which takes the coupling effect of oscillating of tower barrel and the twisting vibration of driven train into account. Using the lumped parameter method, a coupled dynamic model for the megawatt wind turbine drive train is built by considering the flexible tower barrel support effects. Then, the dynamic characteristics of the megawatt wind turbine drive train are analyzed. The Campbell chart is used in this research to analyze the potential resonance points. And the potential resonance frequencies between the cutting in and cutting out rotational speed of the drive train are obtained. Finally, Simpack is used to analyze the dynamic characteristics of drive train and verify the correctness of the proposed method.     

Evaluation and analysis on the extreme load of wind turbine blade

According to the international standard of German GL 2010, a wind turbine of 850 kW is applied to the corresponding wind power generation unit and its situation of pneumatic rated power and sympathetic vibration is analyzed with Bladed software. The result verifies the reliability of wind turbine in operation. Further, after all the wind regimes in GL standard are calculated and analyzed comparatively, the extreme wind regimes which mainly influence the aerodynamic performance of the wind blade are obtained, namely, Dlc4.2b, Dlc1.3a, etc. Later on, the evaluation criteria of wind turbine blade taking the load of blade root as standard are established and implemented with the built-in demo data of Bladed software to testify its generality. Then based on the above evaluation criteria, extreme loads of the 850 kW’s blade root is computed and it’s found the extreme swing load is 353 663 N·m, which is 2.5% lower than its designed value. The result verifies the security of the blade in operation and the reliability of the evaluation criteria.