基于遗传算法的大型风机复合材料叶片根部强度优化设计

为了提高复合材料叶片承担载荷的能力, 尤其是承受最大弯矩的叶片根部的承载能力, 研究了遗传算法的优化原理并将遗传算法应用到复合材料叶片根部铺层的优化设计中。针对复合材料层压结构遗传算法优化设计中, 层压结构参数具有离散型的特点, 提出了适合复合材料层压结构遗传算法优化设计的整数编码策略, 以整数来表征层压结构参数。在分析层压结构强度的基础上, 针对结构强度优化的目标构造了可用于遗传算法的适应度函数。同时参考了一定的铺层规则, 在铺层角度限制为工程中常用的四种角度的前提下, 应用遗传算法对叶片根部进行了铺层优化设计。结果表明, 由于遗传算法特有的处理离散型问题的优势, 在叶片根部的铺层优化设计中应用遗传算法是可行和可信的。     

小型H型垂直轴风车叶片的设计分析

风力发电机(简称风车),是一种将风能转化为机械能,电能或热能的转换装置。比较了垂直轴风力发电机与水平轴风力发电机的优势后,对小型H型垂直轴风车叶片的进行了分析,给出了在不同工作环境中的载荷分析,并对叶片的应力计算及校核方法作了讨论,为小型H型垂直轴风车的叶片设计提供了参考。     

风力发电机叶片的疲劳特性测试

以1.5MW水平轴风力发电机的叶片作为研究对象,通过测试叶片材料的S-N曲线,分析叶片根部的载荷谱,采用Miner疲劳累计理论对叶片的疲劳寿命进行分析评估,探索大型风电机组叶片的疲劳特性,评价叶片设计是否符合要求。结果表明:叶片挥舞方向为风力发电机组的主要损伤方向。     

一种并联机构运动副摆放位置不同的静力学分析

目的运用螺旋理论在Matlab平台上对一种封装并联机构2-RPU/SPR,以及因其运动副摆放位置不同衍生出的3种两转一移并联机构2-UPR/SPR,2-UPR/RPS和2-RPU/RPS的静力学特性进行分析,并比较它们的优劣性。方法文中采用螺旋理论法对4种并联机构建立静力学数学模型,进而运用Matlab编程软件建立4个机构的程序模型,在Matlab中分2种情况对4个机构进行静力学分析。结果机构2-RPU/SPR的驱动力与其他3个机构相比相对较小;机构2-RPU/SPR的等效约束力和驱动力与其他3个机构相比变化波动较小。在动平台输出相同的情况下,机构2-RPU/SPR易于控制与驱动,灵活性高于其他3个机构;在动平台位姿相同的情况下,机构2-RPU/SPR抗外界干扰的能力优于其他3个机构。结论并联机构2-RPU/SPR比另外3个并联机构更好,在高精度包装工程中更具有实际应用前景。     

涡轮分子泵叶片的结构设计与分析

涡轮分子泵是一种精密高速旋转机械,在设计过程中对主轴、转子等关键件的设计作科学准确的计算、校核尤为重要。文章阐述了借助PRO/E、PRO/MECHANICA软件(试用版)对涡轮分子泵的涡轮叶片进行结构设计、有限元分析(应力分析及位移分析),大大提高了设计的准确率、增强了设计的可靠性及缩短了产品的研发周期。把CAD、CAE有效地应用于实际的产品结构设计中,将会对产品的研发起很大的作用。     

影响风机塔顶法兰设计的因素

对影响大型风机塔顶法兰设计的因素进行了分析。模拟结果显示,塔顶法兰的设计受其他零部件尺寸的影响也比较大,不容忽视。对塔顶法兰进行设计时必须考虑到这一点,为以后塔顶法兰的设计提供了有利的依据。     

基于自适应模糊PID的风力发电机叶片角度控制

本文研究了风力发电机倾斜角度控制问题,探讨了自适应模糊PID调节器在该控制系统中的应用。通过仿真试验和分析,验证了自适应模糊PID调节器在不确定模型条件下的稳定性和控制效果。结果表明,与传统PID控制器相比,自适应模糊PID调节器能够更好地响应风力发电机的倾斜角度控制,能够快速、平滑地调节角度并保持稳定。本文可为提高风能利用效率和减少环境污染提供参考,未来可验证其他控制方法以获得更好性能。     

浅谈风电关键部件叶片的结构设计

风电叶片是风力发电设备的关键部件之一,风力发电机组通过叶片将空气的动能转化为机械能,进而由发电机转化为电能。在这个能量转换过程中,风轮及其叶片起着非常重要的作用。本文从风电叶片的材料、结构形式等方面全面研究了叶片的设计技术,并指出叶片在生产应用中的问题和相应的建议,具有很高的实用价值。     

Non-linear dynamic analysis of a wind turbine blade

ABSTRACT

Wind turbine blades’ dynamic behavior must be well investigated during the design process in order to avoid resonance. Modal analysis and nonlinear dynamic analysis of a rotating wind turbine blade are presented in this paper to study the effects of rotation speed on the natural frequencies and displacements. Accordingly, an enhanced finite element formulation based on uncoupled translational and rotational displacements’ kinetic energy was developed. A twisted wind turbine blade was discretized using beam elements with different cross sections; each has six degrees of freedom per node. At rest, the model results were validated using ABAQUS software. Furthermore, the effects of geometrically non-linear phenomena produced by blade displacement on the vibration characteristics of the rotating blade have been discussed. The blade non-linear problem was solved by applying the Newmark method combined with the Newton-Raphson schema. Results show that the blade natural frequencies and displacements increase under angular rotation speed augmentation. This work highlights the significant sensitivity of the blade vibration characteristics to the geometric non-linearity. Accordingly, a modal and a linear analysis are insufficient to precisely estimate the dynamic behavior of a rotating turbine blade.     

Structural optimization procedure of a composite wind turbine blade for reducing both material cost and blade weight

A composite blade structure for a 2 MW horizontal axis wind turbine is optimally designed. Design requirements are simultaneously minimizing material cost and blade weight while satisfying the constraints on stress ratio, tip deflection, fatigue life and laminate layup requirements. The stress ratio and tip deflection under extreme gust loads and the fatigue life under a stochastic normal wind load are evaluated. A blade element wind load model is proposed to explain the wind pressure difference due to blade height change during rotor rotation. For fatigue life evaluation, the stress result of an implicit nonlinear dynamic analysis under a time-varying fluctuating wind is converted to the histograms of mean and amplitude of maximum stress ratio using the rainflow counting algorithm Miner's rule is employed to predict the fatigue life. After integrating and automating the whole analysis procedure an evolutionary algorithm is used to solve the discrete optimization problem.     

A study on structural design and analysis of small wind turbine blade with natural fibre(flax) composite

In recent years, there has been a growing interest in the use of naturally sourced fibres for use in composites design and manufacture. In this work, a structural design on 1-kW-class horizontal axis wind turbine blade using natural flax fibre composite is performed. The structural design results of flax/epoxy composite blade are compared with the design results of glass/epoxy composite blade. In order to evaluate the structural design of the composite blade, the structural analysis was performed by the finite element method. Through the structural analyses, it is confirmed that the designed blade using natural composite is acceptable for structural safety, blade tip deflection, structural stability, resonance possibility and weight.     

基于非线性本构关系的复合材料风机叶片有限元极限分析与设计

为了研究具有三维复杂构形的复合材料风机叶片的逐次破坏过程和极限承载能力, 将复合材料细观力学非线性本构理论桥联模型与有限元软件ABAQUS通过用户子程序UGENS结合起来对风力发电机叶片结构进行极限强度分析。只需提供纤维和基体的材料性能参数、 纤维体积含量以及蒙皮和增强筋的铺层数据包括铺设角、 层厚和铺层数, 就可预报出复合材料复杂叶片结构的整体承载能力以及叶片破坏所处的位置, 为正确评估和合理设计风机叶片结构提供了一种简便有效的分析方法。以一种20kW风机叶片为例, 用此方法实现了新型复合材料叶片结构的极限分析和合理设计, 提高了叶片的强度和刚度, 有效降低了叶片的重量。本文中的方法同样适用于其它复合材料复杂结构的极限分析与强度设计。      

An investigation on the failure of an L-O steam turbine blade

This paper presents an analysis of the cause of steam turbine blade fractures. Recently, several L-0 blades 28.5 in. (725 mm) long of a steam turbine fractured 5 in. (125 mm) from the blade root platform, causing the forced outage of the turbine. A finite-element analysis (FEA) of the blade was carried out in the beginning of the last decade to calculate the natural frequencies and the vibratory stresses on the blade. A telemetry test was also conducted. The current investigation analyzed the operational data during the last two years, reviewed the results of previous studies, conducted metallurgical investigations, and identified the mechanical and metallurgical modes of the failure. The results of the investigations showed that improper welding of the stubs was the principal cause of blade fracture.     

Failure analysis of steam turbine last stage blade tenon and shroud

This paper presents an analysis of the cause of steam turbine blade fractures. Recently, several L-0 blades 28.5 (725 mm) long of a steam turbine fractured 5 in. (125 mm) from the blade root platform, causing the forced outage of the turbine. A finite-element analysis (FEA) of the blade was carried out in the beginning of the last decade to calculate the natural frequencies and de vibratory stresses on the blade. A telemetry test was also conducted. The current investigation analyzed the operational data during the last two years, reviewed the results of previous studies, conducted metallurgical investigations, and identified the mechanical and metallurgical modes of the failure. The results of the investigations showed that improper welding of the shroud to the blade was the principal cause of blade fracture.     

液氦传输管线的支撑设计和静力学分析

液氦传输管线是大型氦低温制冷设备高效运行和冷量运输的保障。为了设计出满足工程要求的管线,采用高真空多层绝热能减少管线的漏热。与此同时,选择合适的支撑结构和布置间距对减少漏热和满足强度要求是十分重要的。采用有限元软件ANSYS对液氦传输管线的支撑和补偿件等进行了静力学分析,结果表明:设计的液氦管线每间隔3 m布置一个支撑能很好的满足强度和减少漏热的要求;同时采用的波纹管进行低温应力补偿,对应力集中点进行了分析,模拟结果能满足强度要求,论证了管道设计的合理性和可行性。     

风力机复合材料柔性叶片的颤振分析

将风力机叶片简化为薄壁复合材料封闭截面弯扭耦合变形梁,基于Hamilton原理并结合变分渐进法（VAM）,建立风力机叶片的气动弹性力学模型。结构模型包括材料各向异性,截面翘曲,离心载荷,科里奥利加速度,以及预锥角和预扭转角的影响。气动载荷采用叶素动量理论和准定常气动力理论进行描述。将位移按广义坐标进行模态展开,采用Galerkin法导出系统的质量、刚度和阻尼矩阵,采用特征值技术进行叶片颤振性能的数值求解。针对周向反对称刚度配置（CAS）叶片进行数值近似计算,揭示了入流比、预扭转角和纤维铺层角等参数对风力机叶片颤振性能的影响。