34m 复合材料风力发电机组叶片屈曲有限元分析[J]
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复合材料风扇叶片力学性能试验研究与有限元分析周睿;刘传辉;金沙;王春生;李忠义【摘要】Static tensile experiments were occupied on a composite fan blade according to the standardized ex-perimental process to verify the mechanical properties required for the normal running of the blades. The test conditions covered the rated condition and the double overloaded condition of the blades. Experimental results have relfected that the composite blades meet the strength and fatigue lifetime requirements of normal operation. The formulation of the experi-mental procedure can provide references on the mechanical performance testing of the similar products. A setting method of composite property used on the CAE modeling of the complicated curving structures was proposed and a ifnite element model of the composite blade was established based on this method. The load-displacement response of the composite blade under the condition of the rated centrifugal force was calculated. Numerical results are in good agreement with ex-perimental results, which indicates that the model is applicable in the analysis of the composite blades.%依照制定的规范化试验流程,进行额定工况和二倍超载工况下的静力加载试验和全寿命周期疲劳试验,以验证复合材料风扇叶片运转工况所需的力学性能试验,结果表明复合材料风扇叶片满足使用强度要求,具有足够疲劳寿命.试验流程制定和具体试验方法可为同类产品力学性能检测提供参考.提出一种曲面外形构件复合材料属性设置方法,基于该方法建立复合材料叶片有限元模型,应用该模型对复合材料叶片在额定工况离心力作用下的载荷-位移响应进行计算.计算所得载荷-位移曲线与试验结果基本吻合,验证了计算方法的合理性.【期刊名称】《航空制造技术》【年(卷),期】2017(000)021【总页数】6页(P85-90)【关键词】复合材料;风扇叶片;试验研究;有限元分析;力学性能【作者】周睿;刘传辉;金沙;王春生;李忠义【作者单位】航空工业空气动力研究院,哈尔滨 150001;航空工业空气动力研究院,哈尔滨 150001;航空工业空气动力研究院,哈尔滨 150001;航空工业空气动力研究院,哈尔滨 150001;航空工业空气动力研究院,哈尔滨 150001【正文语种】中文随着试验空气动力学技术应用的日渐成熟,风洞产业近年来发展良好,多种尺寸、用途的风洞设备大量投入使用。
第31卷 第21期2009年11月武 汉 理 工 大 学 学 报JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGYVo l.31 N o.21 Nov.2009DOI:10.3963/j.issn.1671 4431.2009.21.034复合材料风电叶片结构截面刚度有限元分析潘利剑1,袁 健1,彭超义2,唐先贺1,刘 魁1(1.株洲时代新材料科技股份有限公司,株洲412007;2.国防科学技术大学航天与材料工程学院,长沙410073)摘 要: 建立了某兆瓦级风电叶片各截面沿其法向拉伸后的壳体模型和实体模型,采用有限元分析方法计算出该模型沿集中载荷方向下的位移并代入材料力学方程中,计算出该叶片各截面的弯曲刚度。
将2种不同模型的计算结果与国外技术文件所提供的风电叶片截面刚度进行比较、综合评价。
结果表明,实体单元结合简支梁边界条件计算出各截面刚度结果相对最为接近国外技术文件所提供的数据。
关键词: 复合材料; 风电叶片; 截面刚度; 有限元中图分类号: T K 83文献标识码: A文章编号:1671 4431(2009)21 0129 04Finite Element Analysis for S ection Stiffness of CompositeWind Turbine BladePAN Li j ian 1,Y UAN Jian 1,PEN G Chao yi 2,TAN G Xian he 1,LI U K ui 1(1.Zhuzhou T imes New M aterials T echnolog y Company L T D,Zhuzhou 412007,China;2.School o f Aerospace and M aterial Engineering ,N atio nal U niversity o f Deffense T echnology,Changsha 410073,China)Abstract: T he shell and solid mo del of each section normal stretched of o ne M W composite w ind turbine blade w er e built.T he bending stiffness of each section was calculated by substituting the displacement o f the model under the concentrated load by finite element method into t he material mechanics equat ion.T he analysis r esults were compar ed to the foreign technical data.T he tw o different finite element analysis schemes were evaluated comprehensively at last.T he result indicates that the calculated results of solid mo del with freely suppor ted beam boundary condition agree w ith the foreign technical data best of all.Key words: composites; w ind turbine blade; sect ion st iffness; finite element收稿日期:2009 06 02.基金项目:国家863项目(2007AA 03Z563)和湖南省重大科技专项(2006GK 1002).作者简介:潘利剑(1980 ),男,博士.E mail:xiaopanhrb@163.co m风力发电机的叶片(文中简称为风电叶片)是风电设备的关键部件,其制造成本约占风机总成本的15%~30%。
风力发电机组有限元分析(FEA)Finite Element Analysis (FEA) for wind turbines2007年7月4日4th July 2007风机的有限元分析(FEA)–越来越重要FEA for wind turbines -increasingly important仅仅是几年前,有限元分析还仅仅用于相对简单的模型的计算。
Only a few years ago, FEA was used for relatively simple models目前:Presently:•越来越多的风机部件使用有限元进行分析Increasing number wind turbine components analysed using FEA•越来越多的细节在有限元模型中的体现,例如Increasing amount of detail in FE model for instance°变接触角轴承的表示法variable-contact-angle bearing representation°部件间具有有限摩擦的接触面的表示法(法兰表面的张开和移位)representation of contact between parts with finite friction (opening/ sliding of flange surfaces)°已装配螺栓的详细表示法detailed representation of bolts in assemblies•越来越多的复杂的非线性有限元Increasing number of complex, non-linear FEAFE analysis for wind turbinesFE analysis for wind turbines风机的FEA –在设计中的位置FEA for wind turbines -place in the design processGH 有限元分析过程GH FEA process规范regulations制造限制manufacturing limits 客户经验/偏好client experience/ preference质量quality人员通过Personnel access安装/安全assembly/safety与其他部件的接口interfaces with other components材料限制material limits最优/可接受的设计Optimal /acceptable design设计性能指标Design performance indicators:成本(材料,产品,运输,操作)Cost (material, production,transport, handling)重量Weight 强度StrengthFE analysis for wind turbinesMain bearing assemblyNacelle structureRotor headNacelle extenderBlade sectionPitch bearingPitch bearing plates(on top and bottom of inner race)同一组载荷下不同设计概念的比较comparison of different concepts under identical load sets最终设计尺寸强度的详细分析detailed analysis of strength of final design geometry风机的FEA –在设计中的位置FEA for wind turbines -place in the design process风机的FEA –最新的分析技术FEA for wind turbines -state of art technology德国劳埃德船级社2003版规范GL (Germanisher Lloyd) 2003 regulations有很大一章是对有限元分析的原则性和细节的要求Extensive chapter with general and detailed FEA requirements挪威船级社(丹麦规范)DNV (Danish regulations)对有限元分析的要求很少,认证更具一般性Fewer FEA requirements, more generic in certificationGarrad Hassan的工作符合GL的要求或更进一步Garrad Hassan work to GL requirements or furtherGL 规范GL regulationsGH 分析发展GH analysis development 某个部件的有限元分析—模型和实际之间的小差距FEA for certain components –narrow gap between model and realityGL接受新的或者改进的有限元分析方法acceptance and adoption by GLof new or improved FEAFE analysis for wind turbines叶片Blade•叶片blade•叶根连接blade root connection机械部件Machinery components•轮毂hub•主轴mainshaft•轮毂主轴连接hub to mainshaft connection •锁定销locking pin•其他螺栓连接other bolted connections 机舱结构Nacelle structure•主机架/底盘main frame/ bed plate•发电机架generator frame•轴承座bearing housings塔架Tower•塔顶(包括偏航轴承的影响)tower top (including influence of yaw bearing)•通道口(门,电缆,航空灯)access openings (door, cables, aviation light)•屈曲分析(仅限于非标准门)buckling analysis (only: non-standard doors)风机的有限元分析-模型总结FEA for wind turbines -FE models summarisedFE analysis for wind turbines风机的有限元分析-模型总结FEA for wind turbines -FE models summarised叶片bladeFE analysis for wind turbinesFE analysis for wind turbines风机的有限元分析-模型总结FEA for wind turbines -FE models summarisedNLR线性非线性包括其它结构分析中的刚度影响螺栓的疲劳和极限失效,包括法兰表面的张开/滑移(所以螺栓弯曲)和变桨轴承的影响叶片叶根叶片NLR非线性关系non-linear relationshipSCFBladeblade include stiffness effects in analysis of other structureslinear blade rootfatigue and ultimate failure in bolts, including effects of opening/ sliding of flange surfaces (hence: bolt bending) and pitch bearingnon-linearNLR除了热点应力(计算应力集中系数),还需要对照设计极限应力检查绝对应力σudas well as hot spotstresses (to calculate SCF),absolute stresses are checked against the design ultimatestress, σud应力集中系数stress concentrationfactor对于非线性分析,应力范围I 近似关系适合于用于计算SCF 的载荷循环for non-linear analyses,approximate relationship for stress ranges appropriate for applied fatigue cyclesto calculate SCFFE analysis for wind turbinesyellow = normal contact (friction coefficient 0.2)red = bonded contact ÆMPC algorithm风机的有限元分析-模型总结FEA for wind turbines -FE models summarised机械部件machinery componentsFE analysis for wind turbines风机的有限元分析-模型总结FEA for wind turbines -FE models summarisedNLR非线性非线性非线性螺栓的疲劳和极限失效,包括法兰表面的张开/滑移(所以螺栓弯曲)和任意附近轴承的影响螺栓的疲劳和极限失效,包括法兰表面的张开/滑移(所以螺栓弯曲)和任意附近轴承的影响包括其它结构分析中的刚度影响和非线性接触轮毂对主轴的连接其它螺栓连接主轴成SCF 非线性非线性线性疲劳和极限破坏的应力热点,包括变桨轴承的非线性影响轴上的热点,凹槽或螺纹处的应力集中,包括轴承的非线性影响销和盘的热点轮毂主轴锁定销和锁定盘机械部件(g)pgMachinery componentshubstress hot spots for fatigue and ultimate failure, including non-linear effects of pitch bearings and bolted connectionsnon-linearSCF mainshafthot spots in shaft, stress concentrations at grooves or threads, including non-lineareffects of bearingsnon-linear SCF locking pin and disk hot spots in pin and disk linear SCF hub to mainshaft connection fatigue and ultimate failure in bolts, including effects of opening/ sliding of flange surfaces (hence: bolt bending) and any nearby bearings non-linear NLR other bolted connections fatigue and ultimate failure in bolts, including effects of opening/ sliding of flange surfaces (hence: bolt bending) and any nearby bearings non-linear NLR main bearinginclude stiffness effects and non-linear contact in analysis of other structuresnon-linear风机的有限元分析-模型总结FEA for wind turbines -FE models summarised机舱结构nacellestructureFE analysis for wind turbinesFE analysis for wind turbinesNLR/SCF SCF SCF非线性线性线性线性焊缝疲劳破坏和其它热点,包括法兰张开和偏航轴承的非线性接触焊缝的疲劳破坏模态分析包括其它结构分析中的刚度影响主机架/底盘副属机架/发电机架副属机架/发电机架轴承座机舱结构Nacelle structuremain frame/ bed platefatigue damage at welds and other hot spots, including effects of flange opening and non-linear contact in yaw bearing non-linearNLR/ SCFauxiliary frame/ generator frame fatigue damage at welds linear SCF auxiliary frame/ generator frame modal analysislinear SCF bearing housingsinclude stiffness effects of bearing housing in analysis of other structureslinearTFE analysis for wind turbines塔架tower8-point contactbearing (slewing ring)three bolted connections风机的有限元分析-模型总结FEA for wind turbines -FE models summarisedFE analysis for wind turbines风机的有限元分析-模型总结FEA for wind turbines -FE models summarisedSCF非线性非线性塔筒底部法兰焊缝的疲劳破坏,包括法兰张开的影响焊缝疲劳破坏,洞周围的应力集中,包括法兰张开的效果塔底法兰塔筒地基嵌入环线性压曲抗力系数线性特征值分析,分析方法不限,非均匀或非锥形壳屈居分析SCF非线性线性塔头法兰焊缝疲劳破坏,包括法兰张开和偏航轴承的非线性接触焊缝的疲劳破坏塔头通道口塔架Towertower top fatigue damage at top flange weld including effects of flange opening and non-linear contact in yaw bearing non-linearSCFaccess openings fatigue damage at weldslinear SCFbuckling analysis eigen-analysis of doors outside limits of analytical method, non-uniform or non-conical shellslinearlinear bucklingresistance factortower base flange fatigue damage at bottom flange weld including effects of flange openingnon-linear SCFtower foundation insert fatigue damage at welds, stress concentrations around holes including effects of flange openingnon-linearSCF有限元建模讨论FE modelling Workshop FE modelling讲到的有限元分析有:The following FEA will be presented:•塔筒底部的入口Access door in tower base•塔头法兰焊缝分析Tower top flange weld analysis•主轴分析Mainshaft analysis•轮毂和主轴之间的螺栓连接Bolted connection between hub and mainshaftFE analysis for wind turbinesFE analysis for wind turbines主要有限元目标Main FE modelling goals-重新获得焊趾位置的应力(疲劳分析)Retrieving stresses at weld toe locations (fatigue analysis)-重新获得门位置的von Mises 应力最大值(检查屈服)Retrieving the maximum von Mises stress at door location (check on yield)有限元模型细节FE model specifics-使用体单元而不是壳单元(GL 的要求)solid elements not shells (required by GL)-塔筒截段的高度最小为2.5 ×Dtower section height of minimum 2.5 ×D有限元建模塔筒入口FE modellingTower access door1/12重新获得焊趾位置的应力Retrieving stress results from the FE model at weldlocation推荐EuroCode3/ 国际焊接协会(IIW)Recommendations from EuroCode3/ International Institute of Welding (IIW)reference pointsstructural stresshot spot Fcomputed total stressF0.4*t0.4*t1*tt有限元建模塔筒入口FE modelling Tower access door2/12FE analysis for wind turbinesFE analysis for wind turbinesStep 1•在CAD (SolidWorks).软件中创建3维门模型3D door model created in CAD (SolidWorks).•在CAD 软件中创建面(用于切割焊缝位置的体)surfaces (to be used for cutting the solid at weld locations) created in CAD.•导入CAE 软件imported into CAE.切割CAD 模型中创建的面Cutting surfaces created in CAD package有限元建模塔筒入口FE modellingTower access door3/12Step 2•用导入的面切割导入的体imported solid cut using imported surfaces•创建新体new solids created•用从塔筒向外复制小面(操作后会删除)的方法切割法兰顶部区域(法兰侧焊接位置)flange top area (flange side weld locations) cut by copying small area offset from tower wall (cut areas are deleted after operation)用导入的面切割体Solid is cut by imported areas 顶部区域用复制的面切割(6个)Top area is cut bycopied areas (6 areas)有限元建模塔筒入口FE modelling Tower access door4/12FE analysis for wind turbinesFE analysis for wind turbiness w e e p m e s hStep 3用工作面切割体以便得到扫略网格The solid is also cut by the workplane to make a sweep mesh possible用水平工作面切割Cut by ‘horizontal’workplane有限元建模塔筒入口FE modellingTower access door5/12有限元建模塔筒入口FE modelling Tower access door6/12Step 41 门区域之外的主要塔筒截面是扫略得到的solid95高阶单元The main tower sections outside the door area are sweep meshed with solid95 higher order elements2 门区域截面用面单元(Mesh200)细化The door area cross section is finely meshed with surface (Mesh200) elements3 焊缝附近的位置面网格细化In the vicinity of the weld the surface mesh is refined网格细化Mesh refinementFE analysis for wind turbines有限元建模塔筒入口FE modelling Tower access door7/12Step 5门和周围直接连接的壳用扫略划分网格door and shell immediatelyaround it are sweep meshed门框架区域和塔架主体之间的壳用四面体单元直接划分shell between door frame region and main towermeshed automatically with tetrahedra15200个Solid95单元15200 Solid95 elementsFE analysis for wind turbinesFE analysis for wind turbinesX T Pointing South.Z T Vertically upwards.Y TPointing East.OriginAt each tower station.塔架载荷和挠曲的坐标系协调Co-ordinate systems for tower loads and deflections在CAD 例子中指定的轴和原点axes and origin designated in CAD,example shown here改变坐标系change system of coordinates有限元建模塔筒入口FE modellingTower access door8/12FE analysis for wind turbines对称条件Symmetry condition所有自由度约束Fixed in all DOFM y =1NmStep 6施加单位载荷Mx=1Nm 求解模型model solved with a unit load M x =1Nm应力Stress: vonMises变形比例Scale deformation =1e9有限元建模塔筒入口FE modellingTower access door9/12FE analysis for wind turbines不对称条件Asymmetry condition所有自由度约束Fixed in all DOFM z =1NmStep 7施加单位载荷M y = 1Nm 求解模型model solved with a unit load M y = 1Nm应力Stress: vonMises变形比例Scale deformation =1e9有限元建模塔筒入口FE modellingTower access door10/12FE analysis for wind turbines应力结果用沿焊缝的“移动的”随动局部坐标系Stress results are read in “moving”local coordinate system aligned with weldStep 8焊趾处的3个应力分量three stress components are read at weld toe:1.与焊趾平行的应力stress parallel with weld 2.与焊趾垂直的应力stress perpendicular with weld 3.面内剪应力in plane shear stress有限元建模塔筒入口FE modellingTower access door11/12FE analysis for wind turbinesS tre s s e s a t d o o r w e ld , o u ts id e to w e r w a llAA-6-4-2024681000.511.522.53T o w er h eig h t [m ]S t r e s s [P a ]S x_Mx S y_Mx S xy_Mx S x_My S y_My S xy_My P 1_Mx P 3_MxPosition Name Node X Pos Y Pos MaxPS_Mx Sx_Mx Sx_My Sy_Mx Sy_My [-][-][no][m][m][N/m 2][N/m 2][N/m 2][N/m 2][N/m 2]Door tower wall, outside A 137500.40 2.08-6.31-5.61-2.96-0.188.01Door tower wall, inside B 136260.37 2.19-9.22-6.08-12.04-2.93-13.92Door flange, outside C 199780.40 2.02-7.51-7.38-7.11-6.39-5.92Door flange, inside D 205820.37 2.13-8.09-6.40-8.93-5.08-7.86Base flange, outside E 623090.820.08-8.75-2.55 1.21-8.74 3.58Base flange, insideF622180.550.09-3.93-0.980.36-3.931.20Step 91计算M x 引起的主应力(PS )Principal Stresses (PS) due to M x load calculated 2 画应力结果图Graphs plotted of stress results3 Mx 引起的主应力(PS )的最大值决定热点max. (abs) PS due to the M x load determines hotspot position4 生成影响线矩阵Influence matrix generated有限元建模塔筒入口FE modellingTower access door12/12有限元建模塔顶法兰焊缝分析FE modelling Tower top flange weld analysis1/15Main FE modelling goal决定关联载荷和焊缝的应力(疲劳和极限分析)Determination of the relationship load and stress in weld (fatigue andextreme analysis)FE model specifics有限元模型细节-使用体单元Solid elements will be used-模型中包括部分塔架,法兰,偏航轴承Part of tower, flange, yaw bearing is modelled-非线性分析ÆNon linear analysisÆ-可能有(局部)连接的张开possible (partial) opening of connection-活动支座滚珠接触shifting bearing ball contact-变化的轴承滚珠刚度changing bearing ball stiffnessFE analysis for wind turbines有限元建模塔顶法兰焊缝分析FE modelling Tower top flange weld analysis2/15Step 1导入SolidWorks2维面模型SolidWorks2D model of areas is imported Step 2在轴承座圈位置,模型是由多线组成的面(90根线组成圆)At bearing race positions, areas formed from poly lines (90 lines forming circle) are modelled部分机舱底座part of nacelle bed plate偏航轴承yaw bearing刹车盘brake disk塔头法兰tower top flange塔筒tower sectionFE analysis for wind turbines有限元建模塔顶法兰焊缝分析FE modelling Tower top flange weld analysis3/15 Step 31 用圆来切割模型The circles are used to cut the model2 螺栓的位置需要切割(工作面切割)Cuts are made for bolt position (work plane cut)3法兰焊缝的位置需要切割(工作面切割)Cuts are made at flange weld location (work plane cut)螺栓位置bolt location多线组成的轴承座圈bearing race formed by poly lines螺栓位置bolt location焊缝位置收缩法兰weld locationnecked flangeFE analysis for wind turbinesFE analysis for wind turbinesStep 41 用表面单元划分面的网格areas meshed with surface elements 2 焊缝位置网格细化(关心的区域)mesh refined in weld area (area of interest)网格细化M e sh r e fin e m e nt有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis4/15有限元建模塔顶法兰焊缝分析FE modelling Tower top flange weld analysis5/15Step 5网格沿轴向旋转mesh rotated around axis28000个Solid45 单元28000 Solid45 elementsFE analysis for wind turbinesFE analysis for wind turbinesd ir e cti o n o f i n i t i a l c on t a c td ir e c t i o n o f i n i t i a lc o n t a c t 使用Li n k 10单元的初始应变特性表示间隙R e p r e s e n t a t i o n o f g a p m o d e l l e d u s i n g i n i t i a l s t r ai n p r o p e r t y o fL I N K 10 e le m e nt sStep 7用Link10单元(单元仅受压)表示轴承滚珠Link10 (compression only elements) are modelled to represent the bearing balls有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis6/15FE analysis for wind turbinesStep 8用Beam 4单元表示螺栓Beam 4 elements are modelled to represent the boltsStep 91 模型中包括接触Contact is modelled2 模型中包括“载荷伞”Load umbrella is modelled塔头=载荷施加Tower top =load applicationcontact有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis7/15FE analysis for wind turbinesStep 10载荷步1:通过给螺栓设置温度(收缩梁)实现螺栓预加载Load step 1: Bolt preload step is solved by applying temperature on bolts (contracting beams)结果显示:仅螺栓预载荷(M z =0kNm)Results shown: Only bolt pre load (M z =0kNm)变形比例= 500Scale deformation = 500有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis8/15Step 11载荷步3:分5个子步施加实际Mz弯矩(7000kNm)求解模型Load step 3: Model is solved with realistic Mz moment (7000kNm) in 5 sub steps结果显示:Mz =7000kNmResults shown: Mz =7000kNm变形比例= 100Scale deformation = 100失去接触Loss of contact有限元建模塔顶法兰焊缝分析FE modelling Tower top flange weld analysis9/15FE analysis for wind turbinesFE analysis for wind turbines受压侧Compression side M z =7000kNm Sy stress 受拉侧Tensile side M z =7000kNm Sy stressLoc1Loc2焊趾位置应力最大weld toe location highest stressed有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis10/15FE analysis for wind turbinesNLR between stress and moment at 4 tower top locations-150.00-100.00-50.000.0050.00100.00150.00200.00-8000000-6000000-4000000-20000002000000400000060000008000000moment [Nm]S t r e s s [M P a ]Outside 1Inside 1Outside 2Inside 2-螺栓应力和弯矩的非线性关系Non linear relationship bolt stress and applied moment -M y ,hub 或M z ,hub 载荷时程(旋转坐标系)Load time history M y ,hub or M z ,hub (rotating coordinate sys.)Step 11生成应力/ Nm 焊趾非线性影响关系non linear influence relationship weld toe stress / Nm is generated螺栓应力时程(使用Bladed )bolt stress time history (using Bladed)极限螺栓应力extreme bolt stress寿命周期内疲劳损伤lifetime fatigue damage有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis11/15FE analysis for wind turbinesR e s u lt a n t c o n t a c t a n g le-80.00-60.00-40.00-20.000.0020.0040.0060.0080.0020406080100120140160180200R a d ia l p o s it io n [d e g ]C o n t a c t a n g l e [d e g ]T e n s i le s i d eC o m p r e s s i o n s i d e对于每一个载荷步,可以计算得到合成的接触角For each load step, a resultant contact angle can be calculated接触结果与前面使用固定45度接触角建模时得到的结果十分不同Æ对焊缝位置应力结果影响很大(大概减少20%)Contact results are very different compared to previous modelling with a fixed contact angle of 45 degrees Ælarge influence on stress results weld location (around 20%reduction)Loc1, 受拉侧tensile side Loc2, 受压侧compression side有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis12/15FE analysis for wind turbines检查轴承滚珠接触Check on realism of bearing ball contact轴承面外所有自由度完全约束Outside bearing areais fully constraint in all DOF刚度很高的载荷伞Very stiff load umbrellaF radial = 8000 kN对称条件Symmetry conditions有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis13/15FE analysis for wind turbines无量纲力无量纲位移有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis14/15FE analysis for wind turbines8点接触轴承(回转支承)8-point contactbearing (slewing ring)3个螺栓连接three bolted connections有限元建模塔顶法兰焊缝分析FE modellingTower top flange weld analysis15/15有限元建模主轴FE modelling Mainshaft 1/11主要有限元建模目的Main FE modelling goal指定主轴表面“热点”的位置Allocate hotspot locations on shaft surface产生“热点”周围的影响线矩阵Produce influence matrix for all the foundhotspots有限元模型细节FE model specifics-静态分析(“热点”分析)Static analysis (hotspot analysis)-使用体单元Solid elements will be applied-模型中包括部分轮毂Part of hub is modelled-模型中包括轴承状态(双球滚子形式)Bearing behaviour (double spherical rollerlay-out) is modelledFE analysis for wind turbinesStep 1主轴的SolidWorks3维模型,轮毂和内轴承座圈很重要SolidWorks3D model of mainshaft, hub and inner bearing races is imported Step 2体模型被切开,沿主轴轴向的截面和部分轮毂被留下Solid model is cut and cross section over the length of the shaft and part of hub is left有限元建模主轴FE modelling Mainshaft2/11FE analysis for wind turbinesFE analysis for wind turbinesStep 3Mesh200单元划分面的网格area meshed with Mesh200 elementsStep 4在关键区域首次细化网格initial mesh refined in critical areasStep 5在关键区域二次细化网格(轮毂侧和齿轮箱侧轴承位置)second mesh refined in critical areas (hub side and gearbox side bearings positions)网格细化1Mesh refinement 1网格细化2Mesh refinement 2有限元建模主轴FE modellingMainshaft3/11有限元建模主轴FE modelling Mainshaft4/11 Step 6面网格绕主轴轴线旋转生成solid 95(高阶)体单元模型area mesh revolved around shaft axis to generate asolid model with solid 95 (higher order) elements36200个Solid95单元36200 Solid95 elementsFE analysis for wind turbines有限元建模主轴FE modelling Mainshaft5/11 Step 6用非常细(没有刚度)的shell 93单元划分体模型网格The solid model is meshed with very thin (nostiffness) shell 93 elements.这些单元会在后处理中用于获取模型表面的应力These elements will be used in the postprocessing phase to extract stresses from thesurface of the model6200个shell 93 单元6200 Shell93 elementsFE analysis for wind turbinesFE analysis for wind turbinesStep 7用非线性Link10单元的“蛛网”表示轴承滚子(刚度建模)Spider webs of non linear Link10 elements are modelled to represent the bearing rollers (stiffness is modelled)Link10单元仅用于承受拉伸载荷的建模The Link10 elements are modelled only to take loading under tensile432个非线性Link10单元(仅受拉伸)432 non linear Link10 elements (tensile only option)轴承中心位置的中心节点Central node at bearing centre position把Link 单元连接到内轴承座圈的外表面Link elements are connected to the outside surface of the inner bearing race有限元建模主轴FE modellingMainshaft6/11FE analysis for wind turbinesStep 81 载荷施加点和“载荷伞”建模1 Load application node and load umbrella is modelled2 齿轮箱安装刚度建模(具有恰当刚度的梁单元)2 Gearbox mounting stiffness is modelled (Beam elements with correct stiffness)3 施加边界条件3 Boundary conditions are applied边界条件Boundary conditions齿轮箱安装刚度Gearbox mounting stiffness施加齿轮箱重量Gearbox weight application施加载荷Load application边界条件Boundary conditions有限元建模主轴FE modellingMainshaft7/11FE analysis for wind turbinesStep 9模型上施加了下列载荷:The following loads have been applied to the model 11个单位载荷:11 unit loads:+F x , -F x , +F y , -F y , +F z , -F z +M x , +M y , -M y , +M z , -M z4个变速箱载荷(实际重力载荷):4 Gearbox loads (real gravity loads):+F y , -F y , +F z , -F zShell 93 单元M y = 1NmvonMises 应力Solid 95 单元M y = 1NmvonMises 应力Shell 93 elements M y = 1NmStress=vonMisesSolid 95 elements M y = 1NmStress=vonMises有限元建模主轴FE modellingMainshaft8/11。
风力机叶片的有限元分析学生姓名:卢取专业班级:机械设计制造及其自动化2008级10班指导教师:朱仁胜指导单位:机械与汽车工程学院摘要:通过Solidworks软件对3MW风力机叶片进行建模,然后基于ANSYS 和Workbench分别对其进行模态分析和流固耦合分析,其中流固耦合分析中的结构静力分析部分也使用到了ANSYS Mechanical APDL。
其中模态分析结果表示:叶片的振型以摆振和弯曲为主,其一阶模态频率分别为 0.34Hz,能顺利的避开外在激励频率,避免了共振现象的发生。
流固耦合分析对额定风载进行了数值模拟仿真,通过结构静力分析,对叶片的受力,变形情况有了一个基本的了解,其中叶片在额定风载情况下的最大应力为56MPa,远远低于其实测拉伸强度的720MPa。
在11级风载下的应力云图显示其所受的最大应力为83.8MPa,满足其材料的强度要求。
该分析对进一步的疲劳分析和优化设计等提供了参考和依据。
关键词:叶片建模;模态分析;流固耦合分析;结构静力分析Abstract:Through the Solidworks software build the blade model which power is 3 MW. Then based on the ANSYS and Workbench software,the analysis of modal and fluid-structure interaction.Andthe Static structural analysis is used the ANSYS Mechanical APDL too.The modal analysisresults show that the vibration modes of this blade are presented as Shimmy and bending,Thefirst modes frequency is 0.34Hz.And it can avoid the external excitation frequencywell,Avoid the resonance phenomenon occurs.The analysis of fluid-structure interaction havedo a numerical simulation about Rated wind load,through the Static structural analysis wehave a basic understanding of the stress and deformation about the blade. And the maximumstress of the blade is 56MPa under the rated wind load.Far lower than the Measured tensilestrength of 720MPa.And under the 11 rating wind load.The stress cloud show that maximumstress is 83.8MPa,Meet the strength of the material requirements.This analysis providesa reference and basis for further fatigue analysis and optimization design.Keywords:Blade modeling;Modal analysis;Fluid-structure interaction analysis;Static structural analysis1 概述风能是地球表面大量空气流动所产生的动能,风能量具有取之不尽、用之不竭、就地可取、不需运输、广泛分布、不污染环境、不破坏生态、周而复始、可以再生等诸多优点。
风力发电机叶片结构设计及其有限元分析摘要为了更好地发展我国的风力发电事业,实现风力发电机的国产化,必须深入开展风力机设计、分析方面的研究。
本文根据传统的的叶片设计方法设计了2MW 风力机叶片,并生成三维几何模型,然后利用有限元模拟对叶片进行了振动模态分析,得到各阶振动频率和振型,为防止结构共振提供了依据。
关键词:风力机,叶片,有限元模拟,优化THE FE SIMULATION AND OPTIMAL DESIGN OF WIND TURBINE COMPONENTSABSTRACTIn order to promote the capability of design and manufacturing of wind turbine in China, more study should be done in the field of wind turbine design and analysis. In this paper, a blade for 2MW wind turbine is designed according to the traditional design procedure and the 3D geometrical model is created. Then the modal analysis is done through the FE simulation to get the frequency and mode shape, which provides the theoretic basis to prevent resonance.KEY WORDS: wind turbine, blade, FE simulation, optimization第一章绪论1.1 能源问题及可再生能源的现状与发展受世界经济的发展和人口增长的影响,世界一次性能源消费量持续增加,1990年世界国生产总值为26.5 万亿美元(按1995 年不变价格计算),2000 年达到34.3万亿美元,年均增长2.7%。
风力发电机叶片振动特性有限元分析
风力发电机叶片振动特性有限元分析是一个研究风机叶片在风力发电机系统工作运行
过程中的振动特性的课题,它也是一种按照建模有限元方法分析和研究不同类型叶片在振
动状态下振动情况及因而产生的振动响应特性,以此获得一些振动特性曲线,为叶片的后
续受力分析提供一定的参考依据。
风力发电机的叶片的振动特性受结构特征、工作状态、操纵荷载及其他因素影响,其
中最主要的因素是外界环境的变化和操纵荷载给叶片产生的共振往复运动中叶片失衡所带
来的混沌振动。
叶片失衡可以将能量传递给叶片,使得叶片频率和振动幅值都会发生变化。
工程计算中,通过有限元方法,对特定的叶片进行模拟计算,在计算模型中设置合适
的单元,并考虑叶片的实际特性和外部环境的实际参数,以计算叶片的力学特性和形变性,确定其受力状态。
通过分析叶片的振动行为来确定叶片在持久性受力或短时间受力期间振
动特性和幅值。
有限元分析,是根据对物体空间变形分析结果估计材料应力-应变-弹性模量及其其他
性能特性,以便求解物体力学问题的一种数值分析方法。
通过有限元分析,可以得到叶片
在振动状态下的振动应力、振动分布,还可以建立准确的运动方程,以及使用Matlab等
软件对振动特性曲线进行拟合,以选择合适的叶片安全性和整体能耗最小的解决方案。
通过分析叶片的振动特性,可以更好地理解叶片在振动状态下的运动情况,给出合适
的设计方案,以期提高风力发电机系统效率,不断改进整个发电系统的设计、结构和叶片
运行性能,最终达到长期维护和重复利用叶片的目的。
34m复合材料风力发电机组叶片屈曲有限元分析*李成友周光明黄再兴/南京航空航天大学田卫国/中航(保定)惠腾风电设备有限公司摘要:采用有限元分析的方法解决了叶片的静强度和屈曲稳定性问题。
首先,阐述了利用MSC .Patran建立复合材料叶片的有限元模型的步骤和方法;其次,利用蔡-吴(E.M.Wu) 失效准则和Hill-蔡( S.W.Tsai) 强度理论校核了几种主要承力材料的强度;最后,结合有限元二阶屈曲模态计算结果,讨论了风机叶片结构的屈曲稳定性。
关键词:风力发电机;叶片;复合材料;有限元分析中图分类号:TK83 文献标识码:B文章编号:1006-8155(2008)05-0040-07Finite Element Analysis of Buckling in the 34m Composite Material Wind Turbine BladesAbstract: The aim of this paper is to investigate the static strength and buckling stability of the 34m composite wind turbine blades (CWTBs). Because the geometric shape and boundary of the wind turbine blades are complicated, the finite element method is used to analyze this problem. First, based on the MSC.Patran, the procedures of the finite element modeling for the CWTBs are discussed. Next, the strength of main materials in CWTB is checked with the E.M.Wu failure criterion and S.W. Tsai strength theory. Finally, the buckling stability of the CWTBs is discussed on the basis of calculation for two-order buckling mode of CWTBs.Key words: wind turbine; blade; composite material; finite element analysis0 引言随着世界能源危机的日益严重,以及公众对于改善生态环境要求的呼声日益高涨,风能作为一种清洁的可再生能源日益受到各国的重视[1]。
风力发电具有无污染、安装运行简单、操作维护成本低等优点,但是其最大缺点是风的间歇性,导致风力发电不稳定。
因此需要用可靠的和高效的设备在风力较强的有限时间内最大限度地获得风能[2]。
叶片是风力发电机最重要的部件。
为了最大限度地利用风能,叶片外形根据空气动力学原理设计而成,为了满足叶片质量轻、刚度大、强度高和耐疲劳等特性,叶片主体部分由复合材料制作而成[2]。
风—电转换过程首先从叶片开始,叶片的性能直接关系到风力发电系统的性能。
各国风力发电系统的运行实践表明,叶片是最容易出现故障的部位[3]。
叶片结构发生破坏的两种形式:材料强度不够和结构屈曲[4]。
所以,对叶片进行强度分析和屈曲分析意义重大。
本文借助于有限元工具,从材料强度和结构屈曲两个方面去研究叶片的性能。
目的是确定叶片应力应变分布规律,找出危险点,对危险点处的几种材料进行强度校核。
进而计算叶片的二阶屈曲模态,获得屈曲载荷,验证叶片是否满足屈曲强度要求。
同时,确定结构容易发生屈曲的危险位置。
本文采用商用软件MSC.Patran和MSC.Nastran,其中MSC.Nastran中屈曲分析包括线性屈曲和非线性屈曲分析,在算法上,MSC.Nastran采用先进的微分刚度概念,考虑高阶应变—位移关系,结合MSC.Nastran特征值抽取算法可精确地判断出相应的失稳临界点[5]。
1 有限元模型1.1 几何模型和网格划分叶片由两部分组成:蒙皮和主梁。
蒙皮是将气流转换成叶片转动所需压力的主要部件。
它的设计是基于空气动力学原理,不同的横截面呈现不同的翼型,并有一定的扭转角,叶片的整体外形自叶根到叶尖大致呈锥形(见图1)。
主梁是叶片承受载荷的主要部件。
蒙皮仅承受总载荷的20%,而其他部分由主梁承担。
主梁的横截面呈盒状。
图 1 叶片立体几何模型:蒙皮和主梁图 2 带边界条件和载荷的叶片有限单元模型叶片的主要外形参数见表1。
表1 叶片主要技术参数CATIA V5平台依据各个截面的轮廓线建立模型框架,然后将这个框架传输到有限元前置处理软件PATRAN中,通过截面放样生成叶片的曲面造型。
网格的划分采用三角形单元,三角形单元可以较好地适应复杂的几何边界条件,有利于从几何上去逼近一个任意双曲度的壳体。
在单元数目的选取上进行了多次尝试,实践表明:单元数目的选取有一个最佳范围,小于这个范围,求解精度不够,超过这个范围,对结果精度的提高则很有限,反而会影响求解速度。
通过多次试算选取单元数目为18797。
这个数目既能保证求解问题的精度,又不影响求解速度。
1.2 材料和单元属性的定义叶片的材料主要有:EWFC1050,EZF800,1#布,EWR300和PVC泡沫,其中PVC泡沫的强度与弹性模量相对其他材料很小,考虑PVC泡沫是为了保证结构的几何形状。
材料参数见表2。
由于复合材料层合壳结构的厚度与长度、宽度比足够小(1/10),可以将结构简化为板单元。
叶片是由玻璃纤维以不同的铺设角铺设而成,因此,可将叶片视为层合板模型。
即由相同的单向板以不同的角度铺设而成,首先,定义单向板各个方向的参数(见图3),单向板使用玻璃纤维作为增强材料,环氧树脂作为基体,E11为纤维轴向方向,E22为垂直于纤维轴线方向(即横向),从其性能特点看出,该单向板是2D 正交各向异性板,在Patran里定义单向板为2D Orthotropic材料。
再用Laminate创建层合板模型,如图4所示,通过定义不同的方向角、不同的厚度、材料定义不同的铺层,将所定义的材料赋给有限元模型。
表2 几种主要材料的参数表叶片的铺层情况复杂:沿叶片纵向分布不均,沿叶片横向也是不均匀的,这就给单元属性的赋值带来了很大的困难,采用分段分块定义层合板模型,然后再分段分块将模型赋给单元。
这样最大限度地模拟了叶片铺层的真实情况(见图5)。
图 3 单向板性能特点示意图图 4 复合材料层合板(Laminate)的定义图 5 叶片单元属性分段分块效果图1.3 计算载荷风力机叶片所受的载荷类型是复杂多样的,是由风机运行条件以及外界条件综合确定的。
运行工况和外界工况是采用单独统计的方法得到[6]。
静强度计算仅考虑外界工况。
外界工况分为正常工况和极端工况。
计算所用载荷为25m/s 极端阵风下的极端外界工况。
表3给出了部分截面的25m/s 极端阵风载荷分布情况,载荷由中航(保定)惠腾公司提供。
表3 25m/s 极端风载荷分布所给载荷为各截面上的弯矩,在一个壳体的轮廓线上定义弯矩,在有限元软件里不易实现,所以,需要对所给载荷进行等效处理。
叶片国家标准将作用在单片叶片上的气动力假设为三角形线性载荷分布。
思路:先假设一个分布力,进行计算,这样可以得出在这个分布力作用下的弯矩图,然后与给定弯矩进行比较,不断进行尝试,最终可以找到一个分布力的作用效果与给定的弯矩效果是一致的。
下面是对25m/s 风载的等效过程,以下所有计算只考虑大小,不考虑方向,方向会在有限元软件的载荷定义里考虑。
(1)对)(z M x 的等效首先假设4()17.04 5.4910x q z z -=-⨯,根据公式:22d ()d ()(d d M x Q x q x x x==),可以得出: 420()()d 17.04 2.74510zx x z Q z q z z z C -==-⨯+⎰2530()()d 8.529.1510zx x z M z Q z z z Cz D -==-⨯++⎰根据边界条件:0=z 时,910398.5)(⨯=z M x (有限元计算的结果)。
31000=z 时, 0)(=z M x (假设)(z q x 时满足的条件)。
得: 53.350317-=C ,910398.5⨯=D 所以得出935210398.553.3503171015.952.8)(⨯+-⨯-=-z z z z M x将给定的弯矩数值与通过上式算出的弯矩进行比较,图6给定的载荷x M 与等效x M 对比:系列1代表表3中数据拟合的弯矩图;系列2代表模拟的线性载荷加载后的弯矩 。
从图中很明显看出:数值和趋势趋于一致。
图 6 给定的载荷x M 与等效x M 对比(2)对)(z M y 的等效首先假设5() 2.337.5110y q z z -=-⨯,根据公式:22d ()d ()()d d M x Q x q x x x==,可以得出:520()()d 2.33 3.7510zy y z Q z q z z z C -==-⨯+⎰2530()()d 1.165 1.2510zy y z M z Q z z z Cz D -==-⨯++⎰根据边界条件:0=z 时,81037.7)(⨯=z M y (有限元计算的结果)。
31000=z 时, 0)(=z M y (假设)(z q y 时满足的条件)。
得: 69.47876-=C ,81037.7⨯=D所以得出83521037.769.478761025.1165.1)(⨯+-⨯-=-z z z z M y将给定的弯矩数值与通过上式算出的弯矩进行比较,结果如图7所示:系列1代表表3中数据拟合的弯矩图;系列2代表模拟线性载荷加载后的弯矩效果图。
从图7中很明显看出:效果虽然有一定差别,但是考虑到这个方向的载荷与)(z M x 方向相比很小。
对整个结构的受载效果影响甚微。
图7 给定的载荷y M 与所用载荷y M 对比(3) 对)(z F 的等效首先假设06968.8)(=z f ,根据公式:d ()()d F x f x x=,可以得出: 0()()d 8.06968zz F z f z z C ==+⎰根据边界条件:当0=z 时,51067.2⨯-=F (有限元计算的结果)。
得: 51067.2⨯-=C从而得到:51067.206968.8)(⨯-=z z F将给定的弯矩数值与通过上式算出的弯矩进行比较,结果如图8所示:系列1代表给定的数据拟合的力的曲线;系列2代表所用的线性分布力加载作用后的效果。