水平轴风力机叶片的截面与动力特性分析

风力机叶片在旋转过程中受重力和离心力作用,产生动力刚化导致固有频率增加。文章以NRELPhase VI风力机叶片为对象,在其内部分别添加圆形腹板、单腹板和双腹板,建立3种不同截面的叶片三维模型,并结合复合材料对叶片铺层进行动力学分析。结果表明,叶片采用的铺层方案能有效避免共振,并且3种叶片模型的重量均接近叶片的真实值。在额定转速下,3种腹板叶片的一阶频率增量随腹板的厚度增加而增加,但在两倍额定转速时,单腹板和圆形腹板的一阶频率增量随腹板厚度增加而减少;同时,腹板中的双轴向玻璃布材料以±45°铺设时,一阶固有频率最大,而由动力刚化引起的一阶频率增量较其他角度小。     

兆瓦级水平轴风力机叶片铺层设计参数影响分析

为研究主梁材料及铺层角度对风力机叶片结构特性影响,基于三维建模软件NX二次开发建立风力机叶片几何模型,结合铺层设计并通过CFD方法获取叶片表面压力分布,采用有限元方法对叶片进行结构模态、强度及屈曲分析.结果 表明:碳纤维主梁叶片质量较玻璃钢减轻约8.08％,主梁材料对模态振型影响较小,主梁铺层角度对挥舞方向运动影响更大...     

基于遗传算法的风力机叶片结构铺层厚度优化

从工程角度出发,提出结合有限元法和遗传算法的优化方法,以解决复杂、多变量风力机叶片结构性能最值优化问题。根据复合材料层合板力学特性,推导单层铺层厚度与层合板主应力之间的数学关系,设计改进遗传算法,给出优化流程。以某1.5 MW叶片为对象,最大主应力为优化目标函数,对其进行铺层厚度优化,得到各轴向布在叶片不同部位的优化铺层厚度范围。结果表明:优化后叶片的最大主应力和应变均明显降低,结构性能显著提高,验证了优化方案和方法的正确性和有效性。     

5 MW风力机叶片模态特性分析

为了研究叶片铺层和主梁形式对大型自适应叶片动态特性的影响,利用Ansys软件建立了5 MW风力机叶片的有限元模型.对不同梁帽铺层角度和主梁形式的叶片进行了模态分析,给出了各模型的前十阶固有频率和振型,分析了叶片梁帽铺层角度、主梁形式和转速对风力机叶片固有频率的影响.结果表明：叶片梁帽铺层角度和叶片主梁形式对固有频率具有重要影响;在叶片的弯扭耦合设计过程中,要考虑设计参数对叶片模态特性的影响,以避免叶片发生振动性能失效.     

大型风力机叶片铺层及模态分析

使用ANSYS软件,自下而上建立风力机叶片的有限元模型,使用单元类型SHELL 99对叶片模型实行铺层。运用有限元方法,对几组铺层方案进行叶片的模态分析,结果显示大型风力机叶片梁帽的铺层对频率及相对位移影响最大,增加梁帽铺层数可更好地提升叶片的结构动力学性能。     

E-玻璃纤维/乙烯基酯树脂复合材料拉伸与模态特性分析

对小型风力机叶片铺层结构所用的E-玻璃纤维/乙烯基酯树脂复合材料进行拉伸试验与试验模态分析,对比分析不同种类纤维的拉伸强度、破坏形态与弹性模量等抗拉性能与模态特性,得出以下结论:根据拉伸强度、破坏形态与弹性模量得出单轴向0°层合板的抗拉性能更好;随着层数增加,单轴向0°纤维布对挥舞固有频率的影响最大,双轴向±45°纤维布对扭转固有频率的影响最大;层数与铺设角度对一阶挥舞、扭转振型影响较小;小型风力机风轮的转速较高,可铺设更多的单轴向0°纤维布,以改变其模态特性;为初步探究单层、多层板模态参数间的关联性,分析得出铺层顺序的变化对层合板固有频率的影响最大值为1.45 Hz,并为E-玻璃纤维/乙烯基酯树脂复合材料钢叶片的生产与研究提供基础理论依据。     

复合纤维风力机叶片结构铺层优化设计研究

从工程角度出发,以某1.5 MW叶片为对象,以结构整体性能最优为目标,运用分级优化的策略,采用理论分析、有限元分析与结构优化相结合的方法,建立数学优化模型、目标函数和约束条件,对铺层角度、铺层厚度及铺层顺序分别进行优化,得到叶片的优化铺层方案。优化前后结构分析结果表明:优化后叶片的最大主应力和应变均明显减弱,结构性能显著增强。可验证优化方案和方法的正确性和有效性。     

铺层参数对风力机叶片静态结构性能的影响分析

复合材料风力机叶片的性能因铺层参数的变化而不同,为了优化铺层方案,探讨了铺层参数对风力机叶片静态结构性能的影响。以某1.5 MW风力机叶片距叶根1/3段为对象,建立其有限元模型,计算叶片在极限工况下各截面的载荷;分析该叶片铺层所采用的单、双、三轴向布的基本力学性能,得出可行替代方案。通过对不同铺层角度、铺层顺序和铺层比例的代表性铺层方案进行分析对比,初步得出叶片具有良好性能的铺放参数。在此基础上,优化原有设计方案,结果表明改进后叶片的失效因子和变形明显降低,验证了所得结论的正确性。     

基于气动弹性剪裁的风力机叶片模态分析

本文为研究叶片铺层参数对叶片动态特性的影响,防止叶片产生共振,改善叶片力学特性,建立了1.5 MW风力机叶片的有限元模型,通过改变铺层角度和铺层纤维比例实现多种不同层合板结构的叶片铺层,并对上述各种铺层叶片结构进行了模态分析,获得了各模型的前六阶固有频率和振型,分析了铺层参数影响叶片动态特性的原因。结果表明:复合材料具有显著各向异性,通过改变铺层角度能影响固有频率大小;叶片低阶振型以挥舞和摆振为主,增加0°铺层比例能提高低阶固有频率;叶片高阶模态出现扭转,45°铺层能提高叶片抗扭能力,有利于增加高阶固有频率。     

对比分析不同材料及铺层对叶片力学性能的影响

基于有限元法,利用ANSYS中复合材料模块模拟叶片铺层,并通过CFD软件模拟流场对叶片施加载荷,对叶片进行结构静力学分析和模态分析;对比不同材料及铺层方式对叶片结构的影响,分析造成这种影响的原因。结果表明:不同材料对叶片的力学性能影响巨大,而采用铺层方法能使叶片满足强度和刚度要求,同时减轻质量并且改善共振引起的振动,±45°双铺层能有效分散叶根梁帽处应力。     

基于DMO的风力机叶片细观纤维铺角优化设计

为进一步发挥复合材料铺层参数的可设计性潜力,提出融合离散材料优化法与遗传算法的叶片铺层角度优化方法.构建以细观单元铺层角度为设计变量、刚度最大为目标函数、应力最小为约束条件的叶片细观纤维铺层角度优化数学模型.应用Python语言编写算法求解程序,并与Abaqus软件交互进行求解,得到叶片各单元各层优化的铺层角度、铺层顺...     

Numerical Investigation on Aeroelastic Behavior of Composite Material Plate Excited by Pulsed Air Jet

Nowadays, carbon fiber composite material is becoming more and more popular in aero engine industry due to its high specific strength and stiffness. Laminate carbon fiber composite material is widely used to manufacture the high load wide chord fan blade, containment casing, etc. The aeroelastic behavior of composite product is critical for the optimization of the product design and manufacturing. In order to explore its aeroelastic property, this paper discusses the coupled simulation of aerodynamic excitation applied on laminate composite material plate. Mechanical behavior of composite material plate is different from that of isotropic material plate such as metal plate, because it is anisotropy and has relative high mechanical damping due to resin between plies. These plates to be studied are designed using 4 different layup configurations which follow the design methods for composite fan blade. The numerical simulation of force response analysis mainly uses single frequency mechanical force input to simulate the electromagnetic shakers or other actuators, which could transmit mechanical force to the test parts. Meanwhile, pulsed air excitation is another way to "shake" the test parts. This excitation method induces aero damping into the test part and simulates the unsteady flow in aero engine, which could cause aeroelastic problems, such as flutter, forced response and non-synchronous vibration(NSV). In this study, numerical simulation using coupled method is conducted to explore the characteristics of laminate composite plates and the property of aerodynamic excitation force generated by pulsed air jet device. Modal analysis of composite plate shows that different ply stacking sequences have a significant impact on the plate vibration characteristics. Air pulse frequency and amplitude in flow field analysis are calibrated by hot wire anemometer results. As the air pulse frequency and amplitude are varied, incident angle of flow and layup configurations of plate can be analyzed in details by the simulations. Through the comparisons of all these factors, air pulse excitation property and the aeroelastic behavior of composite material plate are estimated. It would provide a possible way to guide the next-step experimental work with the pulsed air rig. The new composite fan blade design can be evaluated through the process.     

兆瓦级海上风力机叶片设计及模态分析

叶片是风力机的重要构件,对其合理设计十分重要。总结了叶片的设计流程,并选择合理的设计参数,设计出兆瓦级风力机的叶片;在三维绘图软件中建模;应用有限元法,选定叶片的材料参数,在有限元软件中对叶片进行模态分析,确定了叶片的各阶模态振型及各阶频率,并对比分析叶片各阶模态振型结果。结果表明,叶片的固有频率范围与外界的激励的频率范围不重合,因此避免了共振破坏的发生。     

风力机复合材料叶片内部结构典型铺层及分析

叶片为风力发电装置中最核心、最关键的部件之一,其材料的选择对于叶片设计至关重要.大型风力机叶片普遍采用复合材料.将叶片视为一个变截面悬臂梁,基于经典层合板理论和梁帽式铺层方法,利用美国可再生能源国家实验室(NREL)发布的叶片结构分析软件PreComp和BModes计算叶片截面刚度、固有频率以及极限载荷作用下的变形.将计算值和ANSYS软件的分析结果进行比较,结果表明梁帽式铺层方法合理可行,且不影响叶片性能,在实际工程应用中有较大的使用价值.     

OPTIMIZATION CONTROL OF COMPOSITE LAMINATES FOR MAXIMUM THERMAL BUCKLING AND MINIMUM VIBRATIONAL RESPONSE

The problem of maximizing the thermal buckling and minimizing the vibrational response of composite laminates is solved using optimal design and active control procedures. The problem is formulated based on a first-order shear deformation laminate theory with various cases of boundary conditions. The design objective is to maximize thermal buckling using ply thickness and the fiber orientation angle as design variables. The active control objective is to minimize the laminate vibrational response with the minimum possible expenditure of control energy. The vibrational response is expressed in terms of the total elastic energy of the laminate and a penalty functional of closed-loop control force. Liapunov-Bellman theory is used to obtain solutions for controlled deflections and optimal control force. Comparative examples are given for angle-ply antisymmetric laminates subjected to a uniform temperature distribution. A general representation for the design variables is presented such that the ply thickness is a function of the number of layers. Some of the obtained numerical results are compared with their counterparts in the literature.     

Numerical validation of a finite element thin‐walled beam model of a composite wind turbine blade

This paper presents a numerical validation of a thin‐walled beam (TWB) finite element (FE) model of a realistic wind turbine rotor blade. Based on the theory originally developed by Librescu et al. and later extended to suit FE modelling by Phuong, Lee and others, this computationally efficient yet accurate numerical model is capable of capturing most of the features found in large blades including thin‐walled hollow cross section with variable thickness along the section's contour, inner reinforcements, arbitrary material layup and non‐linear anisotropic fibre‐reinforced composites; the present application is, for the time being, restricted to linearity. This one‐dimensional (1D) FE model allows retaining information of different regions of the blade's shell and therefore approximates the behaviour of more complex three‐dimensional (3D) shell or solid FE models more accurately than typical 1D FE beam models. A 9.2 m rotor blade, previously reported in specialized literature, was chosen as a case study to validate the static and dynamic behaviour predicted by a TWB model against an industry‐standard 3D shell model built in a commercial software tool. Given the geometric and material complexities involved, an excellent agreement was found for static deformation curves, as well as a good prediction of the lowest frequency modes in terms of resonance frequencies, mode shapes and frequency response functions; the highest (sixth) frequency mode shows only a fair agreement as expected for an FE model. It is concluded that despite its simplicity, a TWB FE model is sufficiently accurate to serve as a design tool for the recursive analyses required during design and optimization stages of wind turbines using only readily available computational tools. Copyright © 2011 John Wiley & Sons, Ltd.     

风电叶片后缘疲劳加载设备摇臂支架结构优化设计

基于模态叠加理论对风电叶片后缘疲劳加载设备摇臂支架进行模态分析和拓扑结构优化。文章通过对风电叶片后缘疲劳加载模型进行合理简化,对摇臂支架所受载荷进行了等效分析,建立了摇臂支架的有限元模型,进而基于模态叠加法对摇臂支架进行动力学响应分析,得到了各阶次的频率分布情况。最后,以各板件厚度为约束条件,建立以质量最轻为目标函数的数学模型,结合OptiStruct软件得到了优化结果。结果表明,优化后的摇臂支架质量减少了985 kg,且在相同工况下,摇臂支架的变形量减少了4.7 mm,验证了优化后摇臂支架结构的可行性,为后缘加载装备的工程应用提供了理论支撑。     

小型水平轴风力机叶片的振动性能的研究

利用振动与噪声测试和分析系统，对小型300W叶片进行实验模态分析。使用BSWA VS302 USB双通道声学振动分析仪对输入和响应信号进行测量和参数辨识，再通过ME’scope VES软件分析来获得叶片的模态特性参数，可以为今后叶片优化设计提供参考。     

某涡轮增压器涡轮叶片断裂故障分析及改进

针对某涡轮增压器涡轮叶片断裂问题,基于ANSYS有限元软件对该涡轮进行强度分析和振动特性分析.结果 表明:该涡轮一阶自振频率较低,一阶倍频比不满足设计要求,共振导致涡轮叶片断裂.在此基础上对涡轮整体结构进行了优化,优化后涡轮叶片一阶自振频率得到提升,叶片断裂问题得到解决.