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通讯作者:

章定国,E-mail:zhangdg419@mail.njust.edu.cn

中图分类号:TU311.3;TU333

文献标识码:A

文章编号:1672-6553-2023-21(4)-016-011

DOI:10.6052/1672-6553-2022-069

参考文献 1
KOIZUMI M.FGM activities in Japan.Composites Part B,1997,28(1-2):1-4.
参考文献 2
OH S Y,LIBRESCU L,SONG O.Thermoelastic modeling and vibration of functionally graded thin-walled rotating blades [J].AIAA Journal,2012,41(10):2051-2061.
参考文献 3
SONG O O.Spinning thin-walled beams made of functionally graded materials:modeling,vibration and instability [J].European Journal of Mechanics-A/Solids,2003,23(3):499-515.
参考文献 4
OH S Y,LIBRESCU L,SONG O.Vibration and instability of functionally graded circular cylindrical spinning thin-walled beams [J].Journal of Sound and Vibration,2005,285(4-5):1071-1091.
参考文献 5
邹建奇,陆佑方,那景新.转动Timoshenko梁的动力学方程及频率分析 [J].应用力学学报,1996,13(4):119-123,171.ZOU J Q,LU Y F,NA J X.Dynamic equations of rotating Timoshenko beam and its frequency analysis [J].Chinese Journal of Applied Mechanics,1996,13(4):119-123,171.(in Chinese)
参考文献 6
李彬,刘锦阳,洪嘉振.计及剪切变形的Timoshenko梁的刚-柔耦合动力学 [J].计算力学学报,2006,23(4):419-422.LI B,LIU J Y,HONG J Z.Coupling dynamics of Timoshenko beam with shear deformation [J].Chinese Journal of Computational Mechanics,2006,23(4):419-422.(in Chinese)
参考文献 7
潘科琪,刘锦阳.计及剪切变形复合材料梁的刚/柔耦合动力学特性 [J].上海交通大学学报,2009,43(8):1293-1297.PAN K Q,LIU J Y.Rigid-flexible coupling dynamics of composite beam considering shear deformation [J].Journal of Shanghai Jiaotong University,2009,43(8):1293-1297.(in Chinese)
参考文献 8
邓峰岩,和兴锁,张娟,等.旋转Timoshenko梁的动力学分析 [J].航空学报,2006,27(6):1092-1096.DENG F Y,HE X S,ZHANG J,et al.Dynamic analysis of rotating Timeshenko beams [J].Acta Aeronautica et Astronautica Sinica,2006,27(6):1092-1096.(in Chinese)
参考文献 9
ZHOU D,FANG J,WANG H,et al.Three-dimensional dynamics analysis of rotating functionally gradient beams based on timoshenko beam theory [J].International Journal of Applied Mechanics,2019,11(4):1950040.
参考文献 10
DAS D.Free vibration and buckling analyses of geometrically non-linear and shear-deformable FGM beam fixed to the inside of a rotating rim [J].Composite Structures,2017,179(1):628-645.
参考文献 11
曹蕾蕾,裴建中,张学敏,等.功能梯度材料热传导问题的仿真 [J].计算机仿真,2012,29(8):387-390.CAO L L,PEI J Z,ZHANG X M,et al.Simulation method of steady-state heat conduction in functionally graded material [J].Computer Simulation,2012,29(8):387-390.(in Chinese)
参考文献 12
高祥.考虑热效应的功能梯度材料梁的动力学建模与仿真[D].扬州:扬州大学,2021.GAO X.Dynamic modeling and simulation of functionally graded material beams with thermal effect[D].Yangzhou:Yangzhou University,2021.(in Chinese)
参考文献 13
刘锦阳,袁瑞,洪嘉振.考虑热效应的柔性板的刚柔耦合动力学特性 [J].上海交通大学学报,2008,42(8):1226-1232,1237.LIU J Y,YUAN R,HONG J Z.The on rigid-flexible coupling dynamic performance for a rectangular plate considering thermal effect [J].Journal of Shanghai Jiaotong University,2008,42(8):1226-1232,1237.(in Chinese)
参考文献 14
刘锦阳,潘科琪.考虑热效应的复合材料多体系统动力学研究 [J].动力学与控制学报,2009,7(1):9-13.LIU J Y,PAN K Q.Dynamic investigation on composite flexible multi-body system considering thermal effect [J].Journal of Dynamics and Control,2009,7(1):9-13.(in Chinese)
参考文献 15
范纪华,陈立威,王明强,等.旋转中心刚体-FGM梁刚柔热耦合动力学特性研究 [J].力学学报,2019,51(6):1905-1917.FAN J H,CHEN L W,WANG M Q,et al.Research on dynamics of a rigid-flexible-thermal coupling rotating hub-FGM beam [J].Chinese Journal of Theoretical and Applied Mechanics,2019,51(6):1905-1917.(in Chinese)
参考文献 16
黎亮,章定国,郭永彬.变温度场中刚柔耦合功能梯度梁系统的动力学特性研究 [J].振动工程学报,2017,30(1):9-19.LI L,ZHANG D G,GUO Y B.Dynamics of rigid-flexible coupling FGM beam systems in variable temperature fields [J].Journal of Vibration Engineering,2017,30(1):9-19.(in Chinese)
参考文献 17
Liu G R,Gu Y T.A point interpolation method [C].Proceedings of the 4th Asia-Pacific Conference on Computational Mechanics.1999:1009-1014.
参考文献 18
杜超凡,章定国.基于无网格点插值法的旋转悬臂梁的动力学分析 [J].物理学报,2015,64(3):406-415.DU C F,ZHANG D G.A meshfree method based on point interpolation for dynamic analysis of rotating cantilever beams [J].Acta Physica Sinica,2015,64(3):406-415.(in Chinese)
参考文献 19
WANG J G,LIU G R.A point interpolation meshless method based on radial basis functions [J].International Journal for Numerical Methods in Engineering,2002,54(11):1623-1648.
参考文献 20
KANSA E J.Multiquadrics-A scattered data approximation scheme with application to computational fluid-dynamics-Ⅱ solutions to parabolic,hyperbolic and elliptic partial differential equations [J].Computers and Mathematics with Applications,1990,19(8-9):147-161.
参考文献 21
杜超凡,章定国,洪嘉振.径向基点插值法在旋转柔性梁动力学中的应用 [J].力学学报,2015,47(2):279-288.DU C F,ZHANG D G,HONG J Z.A meshfree method based on radial point interpolation method for the dynamic analysis of rotating flexible beams [J].Chinese Journal of Theoretical and Applied Mechanics,2015,47(2):279-288.(in Chinese)
参考文献 22
杨兴,刘仁伟,侯鹏,等.基于一阶剪切板理论的FGM板刚柔耦合动力学建模与仿真 [J].动力学与控制学报,2020,18(4):33-43.YANG X,LIU R W,HOU P,et al.Dynamic modeling and simulation of functionally graded materials plates based on first order shear plate theory [J].Journal of Dynamics and Control,2020,18(4):33-43.(in Chinese)
目录contents

    摘要

    将无网格点插值法和无网格径向基点插值法用于温度场中旋转柔性功能梯度材料梁的动力学分析.在考虑剪切效应的基础上,在梁本构关系中计及热应变,采用4种离散方法描述梁的变形场,运用第二类Lagrange方程,推导出大范围运动功能梯度材料梁的一次近似刚柔耦合动力学方程,研究不同温度变化下梁的动力学响应.通过动力学仿真得出以下结论:温度场对沿横向对称分布的功能梯度材料梁的横向变形影响较小,对纵向变形的影响较大,且在计算温度荷载作用下的梁末端变形时不应忽略轴向变形影响.

    Abstract

    Dynamic analysis of functionally graded material beams using meshless point interpolation method and radial basis point interpolation method. On the basis of considering the shear effect,the thermal strain is also included in the constitutive relationship of the beam. The deformation field of the beam is discretized by four discrete methods,the first-order approximate rigid-flexible coupling model of the functionally graded material beam with large overall motion is derived via Lagrange’s equations of the second kind,and the dynamic response of the beam under different temperature fields is studied. The simulation results show that the temperature field has little influence on the transverse deformation of the functionally graded material beam with transverse symmetry distribution,but has great influence on the longitudinal deformation. The influence of axial deformation should not be ignored in the temperature field.

  • 引言

  • 工程结构中的直升机旋翼叶片、机械臂和涡轮机叶片等正朝着更高的运行速度和精度的方向发展.这些系统由刚性基座和连接在其上的柔性附件组成,是典型的刚柔耦合系统,可简化为旋转柔性梁系统进行动力学分析.在实际应用中,系统往往处于高温、高转速等工况,传统的均质材料由于其自身力学性能的局限性,已很难满足实际服役环境的要求.因此,在不影响结构强度的前提下,设计出满足服役环境要求的新型复合材料并研究其动力学特性尤为重要.此外,多体系统动力学的相关理论大都采用Euler-Bernoulli梁进行研究,该理论只适用于计算细长梁,对于长细比较小的梁系统,由于Euler-Bernoulli梁理论忽略了剪切效应,会导致一定的系统误差.

  • 在众多新型复合材料中,功能梯度材料[1](Functionally graded material,FGM)以其耐热、高强度、改善应力集中等优越性而被研究人员广泛关注,并将其应用于航空航天、核工业及生物等领域.Librescu等[2]首次对热荷载作用下的功能梯度材料叶片进行动力学建模,重点分析了体积分数、温度梯度、截面长宽比、预扭力、轴向压缩载荷等因素对旋压梁振动和失稳的影响; 之后讨论了功能梯度材料和绕其纵轴匀速旋压的圆柱形薄壁梁的热弹性建模和行为有关的问题.邹建奇等[5]在转动理论的基础上推导出Timoshenko梁的动力学方程,研究了梁在不同条件下的固有频率特性.李彬等[6]在Timoshenko梁理论的基础上,利用虚功原理推导出系统的动力学方程,经数值仿真得出以下结论:当梁为细长梁时,剪切变形对柔性梁的影响较小,而随着梁的横截面积与惯性矩比值的减小,剪切作用对梁的影响逐渐明显.潘科琪等[7]利用假设模态法对计及剪切变形的复合材料梁进行仿真计算,研究Euler-Bernoulli梁和Timoshenko梁固有频率的差异,研究复合材料梁计及剪切作用时引起的挠度变化与均质材料动力学特征的差异性.邓峰岩等[8]运用有限元法对Timoshenko梁的变形进行离散,研究不同条件下梁的末端变形和频率计算以及剪切作用对梁的影响.Zhou等[9]基于Timoshenko梁的相关理论研究FGM梁的三维动力学,假定泊松比不发生变化,在Hamilton原理的基础上确定控制方程,研究变形间的耦合量、无量纲角速度、功能梯度指数和长细比对振动特性的影响.Das[10]在Timoshenko梁理论的基础上,采用哈密顿原理推导得到系统的动力学方程,对旋转功能梯度材料梁系统的自由振动频率进行了相关研究.曹蕾蕾等[11]利用无网格数值算法构造FGM的热传导方程,对梁的温度分布进行数值仿真.高祥[12]基于Euler-Bernoulli梁理论,采用无网格法对有温度载荷作用的FGM梁进行动力学建模,对不同参数条件下的FGM梁动力学特性进行研究,验证了无网格法的准确性及优点.刘锦阳等[13]建立了考虑热效应作用下板的动力学方程,研究不同温度条件下系统的动力学特征.在几何非线性的理论基础上,研究了温度场中作大范围运动的梁和板的刚-柔耦合问题.杨兴等[22]基于一阶剪切板理论,采用有限元法对FGM板刚柔耦合动力学问题进行了研究.范纪华等[15]基于假设模态法对变截面的FGM梁进行了仿真计算,针对FGM梁在外部高温、内部冷却情况下的刚-柔-热耦合动力学进行了深入研究.结果表明,由于功能梯度材料的分布,受热荷载作用的FGM梁横向变形被抑制.黎亮等[16]研究了三种温度场中的两种材料分布规律下的FGM梁的动力学特征,分析了温度和功能梯度指数对系统的动力学影响,并对比温度场下两种梯度分布规律的FGM梁末端响应.数值仿真可以看出,梁末端响应与集中质量的大小和其位置以及材料的分布规律有极大的联系.综上所述,对梁的变形场离散方法大都采用假设模态法和有限元法.假设模态法虽计算效率高,但基于小变形假设理论,当变形较大时会产生较大的计算误差,且描述复杂结构或不规则形状时选取模态较为困难; 有限元法理论成熟,被广泛应用于工程中各个领域,但由于单元的限制,不易构造高阶连续的形函数,且单元间存在应力不连续的问题.为了克服有限元法对单元的依赖,无网格法应运而生.该方法不需要预定义的网格信息,可很简单地构造高阶形函数,具有更高的精度.对于采用无网格法描述梁的变形场,同时考虑剪切效应和热效应并附加集中质量的旋转FGM梁刚-柔耦合动力学问题的研究尚不多见.

  • 本文主要创新点是基于计及剪切效应的Timoshenko梁理论,采用无网格法,建立热效应下附加集中质量的FGM梁一次近似刚-柔耦合动力学模型,研究了温度场、剪切效应及附加集中质量对旋转FGM梁动力学特性的影响.将无网格点插值法[17]和径向基点插值法[19]的仿真结果与传统的假设模态法和有限元法进行对比,验证无网格法的正确性和可推广性,同时说明假设模态法并不适用于变形较大的工况.本文研究成果可丰富柔性多体系统动力学领域的离散方法,为解决实际工程问题提供理论基础.

  • 1 动力学模型

  • 1.1 物理模型

  • 图1为有集中质量作用的FGM梁系统,FGM梁与半径为a的中心刚体以固结的方式连接,并绕Z轴转动.Joh为其转动惯量,其中OXY为以O点为原点建立的惯性坐标系,在FGM梁上建立浮动坐标系oxyOX轴与ox轴的夹角为θτ为作用于中心刚体上的外力矩,梁的长度、宽度和厚度分别为lbh.集中质量为mt,其与中心刚体间的距离为lt.

  • 图1 FGM梁变形示意图

  • Fig.1 The deformation of FGM beam

  • FGM梁由陶瓷和金属复合而成,材料沿厚度方向分布,外侧为陶瓷材料,内部为金属材料,分别用下标c、m表示,N为其功能梯度指数.其中,密度ρ、弹性模量E、热膨胀系数α和热传导系数K均沿梁厚度呈幂律分布,分布规律为:

  • E(y)=Ec-Em2yhN+Emρ(y)=ρc-ρm2yhN+ρm
    (1)
  • K(y)=Kc-Km2yhN+Kmα(y)=αc-αm2yhN+αm
    (2)
  • 1.2 FGM梁的热传导方程

  • 本文研究稳态温度场下的动力学特性,即FGM梁承受的温度载荷与时间的变化无关,只根据FGM梁的材料分布规律沿厚度方向呈梯度分布.则热传导方程的表达式为:

  • -ddyK(y)dTdy=0
    (3)
  • 其边界条件为:

  • T(h/2)=TcT(-h/2)=TcT(0)=Tm
    (4)
  • 将式(4)代入式(3),运用泰勒级数对其进行展开求解,从而得到FGM梁所在温度场的梯度表达式:

  • T(y)=Tm+ΔTC2yh-Kcm(N+1)Km2yhN+1+Kcm2(2N+1)Km22yh2N+1-Kcm3(3N+1)Km32yh3N+1+Kcm4(4N+1)Km42yh4N+1-Kcm5(5N+1)Km52yh5N+1
    (5)
  • 式(4)、式(5)中的一些相关参数如下所示,其中Tm为材料的边界温度.

  • ΔT=Tc-Tm
    (6)
  • Kcm=Kc-Km
    (7)
  • C=1-Kcm(N+1)Km+Kcm2(2N+1)Km2-Kcm3(3N+1)Km3+Kcm4(4N+1)Km4-Kcm5(5N+1)Km5
    (8)
  • 1.3 FGM梁的动能和势能

  • 在惯性坐标系中,集中质量块mt的矢径为:

  • rmt=ΘrA+ρ1+u1
    (9)
  • 式(9)中的具体参数如下:

  • ρ1=lt,0T
    (10)
  • u1=ux1,vy1T
    (11)
  • 其中,rA为刚体质心Oo的矢径u1在浮动基下的坐标为:

  • ux1=w1+wc-yφ
    (12)
  • vy1=v1+v2
    (13)
  • 式(9)对时间t求一次导数,得到集中质量的变形速度,表示为:

  • r˙mt=Θ˙rA+ρ1+u1+Θu˙1
    (14)
  • 因此,系统的总动能为:

  • W=12V ρ(y)r˙Tr˙dV+12Johθ˙2+12mtr˙mtTr˙mt
    (15)
  • 式(15)前两项为FGM梁的动能,后一项为集中质量的动能.

  • 纵向正应变ε11为:

  • ε11=w1x-yφx
    (16)
  • 剪切应变为:

  • γ=vx-φ
    (17)
  • 不考虑FGM梁的扭转效应,则系统的弹性势能为:

  • U=12V E(y)ε112dV+12V GkγTγdV
    (18)
  • 2 温度场中计及剪切效应的FGM梁的动力学方程

  • 取纵向和横向位移函数为:

  • w1(x,t)=Φ1(x)A(t)w2(x,t)=v1(x,t)+v2(x,t)=Φ2(x)B(t)+Φ3(x)C(t)
    (19)
  • 式中,Φ1x)、Φ2x)和Φ3x)分别为w1v1v2所对应不同离散方法形函数的行阵,At)、Bt)和Ct)分别为w1v1v2的相应列阵,四种离散方法的形函数在文献[1821]中有详细的阐述.

  • 横向位移引起轴向位移的非线性耦合变形量为:

  • wc=-12BTH(x)B
    (20)
  • 式中,Hx)为耦合形函数,其表达式为:

  • H(x)=0x Φ2'T(ξ)Φ2'(ξ)dξ
    (21)
  • 取系统的广义坐标列向量q=( θATBTCTT,温度载荷对FGM梁所做的虚功为:

  • δWT=V δεxσTdV=V δεxE(y)(-α(y)θ)dV=QTTδq
    (22)
  • 式中,θ=T-T0为温差,T为实际温度,T0为初始参考温度,在本次研究中取零; σT为热应力; QT为温度荷载下的广义力列矩阵,其公式为:

  • QT=0-h2h2 E(y)bα(y)Tdy0l φ'xdx--h2h2 yE(y)bα(y)Tdy0l φ''ydx0
    (23)
  • 外驱动力矩所做虚功为:

  • δWD=QτTδq
    (24)
  • 上式中,Qr=[Fr 0 0 0]是外驱动力对应的广义力列阵,运用第二类Lagrange方程:

  • ddtWq˙-Wq=-Uq+QT+Qτ
    (25)
  • 将FGM梁的动能式(15)及势能式(18)代入式(25),可得考虑剪切效应和温度场的附加集中质量的中心刚体-FGM梁的一次近似刚柔耦合系统动力学方程为:

  • (26)
  • 式(26)中的具体矩阵如下所示:

  • M11=Job+J2+2SxA+ATM1A+BTM2B-BT(aF+D)B_+CTM4C+2BTM6C__
    (27)
  • M22=M1
    (28)
  • M33=M2
    (29)
  • M44=M4__
    (30)
  • M21=M12T=-M3B-M5TC__
    (31)
  • M31=M13T=SyT+M3TA+Y
    (32)
  • M41=M14T=SzT+M5TA__
    (33)
  • M32=M23T=0
    (34)
  • M24=M42T=0
    (35)
  • M34=M43T=M6__
    (36)
  • Qθ=τ-2θ˙SxA˙+ATM1A˙+BTM2B˙-BT(aF+D)B˙_+CTM4C˙-B˙TM6C+BTM6C˙__
    (37)
  • QA=θ˙2SxT+2θ˙M3B˙+θ˙2M1-K1A+2θM5C˙˙__+K2B-K5
    (38)
  • QB=θ˙2M2-aF-D_B-2θ˙M3A˙K3B+K2A+K6
    (39)
  • Qc=θ˙2M6B-2θ˙M5A˙+θ˙2M4-K4C__
    (40)
  • 式中单下画线的项是考虑了非线性耦合变形量wc产生的附加耦合项,双下画线为考虑剪切效应产生的相关项,K5K6为温度荷载项.相关常数矩阵为:

  • Job=0l ρbh(a+x)2dx+a+lt2mt
    (41)
  • J2=V ρy2dV
    (42)
  • Y=V ρy2Φ2'(x)dV
    (43)
  • Sx=0l ρbh(a+x)Φ1(x)dx+a+ltΦ1ltmt
    (44)
  • Sy=0l ρbh(a+x)Φ2(x)dx+R+ltΦ2ltmt
    (45)
  • Sz=0l ρbh(a+x)Φ3(x)dx+R+ltΦ3ltmt
    (46)
  • M1=0l ρbhΦ1T(x)Φ2(x)dx+Φ1TltΦ2ltmt
    (47)
  • M2=0l ρbhΦ2T(x)Φ2(x)dx+Φ2TltΦ2ltmt+v ρ(y)y2Φ2'T(x)Φ2'(x)dV
    (48)
  • M3=0l ρbhΦ1T(x)Φ2(x)dx+Φ1TltΦ2ltmt
    (49)
  • M4=0l ρbhΦ3T(x)Φ3(x)dx+Φ3TltΦ3ltmt
    (50)
  • M5=0l ρbhΦ1T(x)Φ3(x)dx+Φ1TltΦ3ltmt
    (51)
  • M6=0l ρbhΦ2T(x)Φ3(x)dx+Φ2TltΦ3ltmt
    (52)
  • D=0l ρbhxH(x)dx+ltHltmt
    (53)
  • K1=0l E1bΦ1'T(x)Φ1'(x)dx
    (54)
  • K2=0l E2bΦ1'T(x)Φ2''(x)dx
    (55)
  • K3=0l E3bΦ2''T(x)Φ''2(x)dx
    (56)
  • K4=V G(y)kΦ3'T(x)Φ3'(x)dV
    (57)
  • K5=0l E4Φ1'(x)dx
    (58)
  • K6=0l E5Φ2''(x)dx
    (59)
  • ρ=1h-h2h2 ρ(y)dy
    (60)
  • E1=-h2h2 E(y)dy
    (61)
  • E2=-h2h2 E(y)ydy
    (62)
  • E3=-h2h2 E(y)y2dy
    (63)
  • E4=-h2h2 [E(y)bα(y)T(y)]dy
    (64)
  • E5=-h2h2 [yE(y)bα(y)T(y)]dy
    (65)
  • 3 动力学仿真

  • FGM梁作大范围运动的规律已知时,给定其旋转角速度的变化规律为:

  • (66)
  • 式中T0=2s,刚体角速度θ˙达到稳定转动状态,其稳定转动状态下的转速为Ω0.

  • 图2 功能梯度材料梯度分布图

  • Fig.2 Gradient distribution of functionally graded materials

  • FGM梁的物理参数取值为:中心刚体的半径a=0,梁长度l=5m,宽度b=0.02m,高度h=0.02m.集中质量位于梁的末端lt=5m,集中质量mt=1kg,剪切系数k=3/2,泊松比μ=0.3,Ec=1.51×1011Pa、Em=7.0×1010Pa,ρc=3.0×103kg/m3ρm=2.707×103kg/m3Kc=2.09W/mK、Km=204W/mK,αc=1×10-5αm=2.3×10-5.图2为功能梯度材料的梯度分布图.

  • 对三种不同的温度场下FGM梁的动力学特性进行研究:第一种为无温度场,即Tc=Tm=0,在此温度场下,FGM梁无温度载荷作用; 第二种为Tc=Tm=10K,在此温度场下,有恒温载荷作用于FGM梁; 最后一种为变温度,即Tc=10K和Tm=0K,在此温度场下,FGM梁受沿厚度方向呈梯度分布的温度载荷的作用.有限法选取10个单元,点插值法及径向基点插值法将问题域离散成11个节点,取假设模态法的模态截断数为3.

  • 图3 FGM梁的末端纵向变形(T=0-0K)

  • Fig.3 The longitudinal deformation at the tip of FGM beam (T=0-0K)

  • 图3(a)为功能梯度指数N=1,无温度荷载作用下,旋转速度Ω0=0.4rad/s时梁末端的二次耦合变形量wc,图3(b)为FGM梁末端的轴向变形量,图3(c)为FGM梁末端纵向变形量u1.由图可知,四种离散方法的变形曲线基本一致,且与文献[16]结果一致,验证模型的正确性,同时也说明当FGM梁的长厚比(梁长度与厚度的比值)较大时,剪切效应对梁末端响应的影响较小.当FGM梁的旋转速度较小时,其末端的轴向变形量相对于末端耦合变形量为低阶小量,在计算FGM梁末端的纵向变形量时可以忽略不计.所以,当无温度载荷作用时,FGM梁末端的纵向位移u1主要是受其二次耦合变形量wc的影响.图4(a)为FGM梁末端的横向变形,图4(b)为FGM梁末端的横向变形速度,四种离散方法的计算结果曲线基本重合,且与文献值一致,进一步验证本文新建模型的正确性.

  • 图4 FGM梁末端的横向变形(T=0-0K)

  • Fig.4 The transverse deformation at the tip of FGM beam (T=0-0K)

  • 图5 FGM梁末端的纵向变形(T=10-10K)

  • Fig.5 The longitudinal deformation at the tip of FGM beam (T=10-10K)

  • 图5表示功能梯度指数N=1,温度场T=10-10K环境下转速Ω0=0.4rad/s时FGM梁的变形曲线,图5(a)、5(b)和5(c)分别为FGM梁末端的二次耦合变形量wc、轴向位移w1和纵向变形量u1.从图中可以看出,温度场对非线性耦合变形量的影响并不明显,但对轴向变形影响明显,在热载荷冲击下,轴向变形出现高频振荡,其振荡幅值约为0.00072m,且FEM、PIM和RPIM仿真结果基本一致,与AMM有明显不同,进一步说明假设模态法的不足.图5(c)与图5(a)的变化趋势基本一致,由于梁末端轴向变形w1的振荡现象,其纵向变形也出现明显的振荡现象.因此,与不考虑温度场相比,当有温度荷载时,不能忽略轴向变形w1的影响.图6(a)为FGM梁末端的横向变形,图6(b)为FGM梁末端的横向变形速度,四种离散方法的动力学仿真曲线与文献[16]近似一致且没有出现明显振荡,说明温度场对横向变形影响很小.

  • 图6 FGM梁末端的横向变形(T=10-10K)

  • Fig.6 The transverse deformation at the tip of FGM beam (T=10-10K)

  • 图7表示功能梯度指数N=1,温度场环境T=10-0K下转速Ω0=0.4rad/s时FGM梁末端的纵向变形量,由图可知,梁末端的二次耦合变形未出现振荡现象,轴向变形图出现明显振荡现象,振荡幅值约为0.00025m,较温度场T=10-10K环境下更为平稳,假设模态法的仿真结果依然有较大误差.图8为FGM梁末端的横向变形和横向变形速度,四种离散方法的动力学仿真曲线与文献[16]近似一致且没有出现明显的振荡现象,与不考虑温度场的仿真曲线基本重合.

  • 图7 FGM梁末端的纵向变形(T=10-0K)

  • Fig.7 The longitudinal deformation at the tip of FGM beam (T=10-0K)

  • 图8 FGM梁末端的横向变形(T=10-0K)

  • Fig.8 The transverse deformation at the tip of FGM beam (T=10-0K)

  • 图9 FGM梁末端的横向变形(Ω0=10rad/s)

  • Fig.9 The transverse deformation at the tip of FGM beam (Ω0=10rad/s)

  • 图9为转速Ω0=10rad/s,其他条件不变,弹性模量同时缩小10倍时梁末端的横向变形图,随着转速的增大,末端横向变形也增大.由图可知,假设模态法的仿真结果发散,而其他三种方法的仿真结果收敛且基本一致.因此,基于小变形假设的假设模态法仅适用于小变形情况,并不能处理大变形问题,而本文所用无网格法具有更广泛的适用范围.

  • 图10 FGM梁末端的横向变形(Ω0=0.4rad/s)

  • Fig.10 The transverse deformation at the tip of FGM beam (Ω0=0.4rad/s)

  • 图11 FGM梁末端的横向变形

  • Fig.11 The transverse deformation at the tip of FGM beam

  • 图10为Ω0=0.4rad/s时,径向基点插值法计算三种温度场下计及剪切效应的不同厚度FGM梁末端的横向变形,图10(a)取h=0.02m,图10(b)取h=0.4m.可以看出不同厚度的FGM梁在受恒温荷载或梯度变温荷载作用下其末端横向变形均与无热荷载作用下的梁末端位移曲线一致.由此可见,温度场对计及剪切效应的FGM梁末端横向变形的影响较弱,且不受梁厚度的影响.

  • 图11为上述参数下,取不同的梁厚度和转速时,考虑剪切和无剪切的FGM梁末端的横向变形图,温度场取Tc=10K和Tm=0K.对比图11中的(a)、(b)、(c)可以看出,在温度荷载的作用下,当FGM梁的厚度取值较小时,考虑剪切效应和无剪切的FGM梁末端横向变形曲线仍基本一致,剪切效应对梁的影响可以忽略不计; 随着梁厚度变大,无剪切作用和剪切效应下梁的末端变形偏差逐渐增大,且梁厚度越大,其末端横向变形越小.此外,对比图11(b)、(d)可知,转速越大,梁末端横向变形亦越大,剪切效应的影响也更大.

  • 图12 FGM梁末端的横向变形(Ω0=0.4rad/s)

  • Fig.12 The transverse deformation at the tip of FGM beam (Ω0=0.4rad/s)

  • 图12为计及剪切效应的FGM梁在不同长度下的末端横向变形,取h=0.2m,Ω0=0.4rad/s,温度场T=10-0K.从图中可以看出,随着FGM梁长度的减小,剪切效应的影响愈加明显,FGM梁末端的横向位移也逐渐减小,因此,当厚长比较大时,剪切效应不可忽略.

  • 图13(a)、(b)分别为不同功能梯度指数下FGM梁在三种温度场中末端的最大横向变形和稳态响应振幅,取h=0.02m,Ω0=0.4rad/s.由图可见,FGM梁末端的最大横向变形和稳态响应幅值与功能梯度指数N呈正相关,且当N增大到一定值时,其随着N的变化趋势趋于平缓.

  • 图13 FGM梁末端的最大横向变形和稳态响应振幅

  • Fig.13 The maximum transverse deformation and steady-state response amplitude at the tip of FGM beam

  • 图14 FGM梁末端的横向变形(Ω1=0.4rad/s)

  • Fig.14 The transverse deformation at the tip of FGM beam (Ω1=0.4rad/s)

  • 图14为不同功能梯度指数条件下计及剪切效应的FGM梁末端的横向变形图,取h=0.4m,Ω0=0.4rad/s,温度场T=10-0K.由图可见,随着功能梯度指数的增大,梁的横向变形也随之增大,说明功能梯度指数可以改变系统的柔度.

  • 图15 FGM梁末端的横向变形(Ω0=0.5rad/s)

  • Fig.15 The transverse deformation at the tip of FGM beam (Ω0=0.5rad/s)

  • 图15(a)为温度场T=10-0K,FGM梁末端作用不同附加集中质量时,梁末端的横向变形图.图15(b)为在FGM梁的不同位置作用附加集中质量时,梁末端的横向变形图.从图中能够看出:FGM梁末端作用的附加集中质量越大,梁末端的横向变形越大; 集中质量距中心刚体越远,梁末端的横向变形越大.

  • 表1 不同方法下的计算相对时间、转速恒定时响应振幅和相对误差(T=10-0K)

  • Table1 The relative time, response amplitude and relative error in different methods (T=10-0K)

  • 表1及表2分别为在温度场取T=10-0K、T=10-10K时,不同离散方法下的计算相对时间、响应振幅和计算相对误差.在旋转速度Ω0=0.4rad/s下,有限法选取10个单元,点插值法及径向基点插值法将问题域离散成11个节点,取假设模态法的模态截断数为3,由表可知,这几种方法的计算效率和振幅基本一致,且同一方法在不同温度场中的计算精度也较为相似.

  • 表2 不同方法下的计算相对时间、转速恒定时响应振幅和相对误差(T=10-10K)

  • Table2 The relative time, response amplitude and relative error in different methods (T=10-10K)

  • 4 结论

  • 本章对温度场中考虑剪切效应的功能梯度材料梁的动力学特性进行研究,运用四种离散方法对作大范围旋转运动的FGM梁系统进行动力学仿真计算,结论如下:

  • (1)当系统没有温度载荷作用时,在旋转速度较低的情况下,计算梁末端纵向变形时可忽略轴向变形的影响,梁末端的纵向变形主要为FGM梁末端的二次耦合变形.而在温度场中,FGM梁末端的轴向变形曲线出现明显的振荡现象,且梯度变化的温度场产生的振荡效应比恒定温度场的弱.因此,在温度场中不能忽略轴向变形的影响.由于FGM梁材料呈对称分布形式,因此温度场对FGM梁末端横向变形的影响较弱.传统的假设模态法只适用于小变形工况,当变形较大时并不适用,而无网格法没有此限制.

  • (2)大范围运动规律已知时,当FGM梁厚度较小或梁长度较大,即长厚比较大时,其剪切效应对梁的影响较小.随着长厚比的减小,剪切效应对FGM梁末端变形的影响也随之增大.且随着功能梯度指数的增大,FGM梁末端横向变形也逐渐增大,当功能梯度指数增大到一定数值时,变化趋于平缓.

  • (3)FGM梁末端作用的附加集中质量越大,梁末端的横向变形越大; 作用的集中质量与中心刚体的距离越远,梁末端的横向变形亦越大.

  • 参考文献

    • [1] KOIZUMI M.FGM activities in Japan.Composites Part B,1997,28(1-2):1-4.

    • [2] OH S Y,LIBRESCU L,SONG O.Thermoelastic modeling and vibration of functionally graded thin-walled rotating blades [J].AIAA Journal,2012,41(10):2051-2061.

    • [3] SONG O O.Spinning thin-walled beams made of functionally graded materials:modeling,vibration and instability [J].European Journal of Mechanics-A/Solids,2003,23(3):499-515.

    • [4] OH S Y,LIBRESCU L,SONG O.Vibration and instability of functionally graded circular cylindrical spinning thin-walled beams [J].Journal of Sound and Vibration,2005,285(4-5):1071-1091.

    • [5] 邹建奇,陆佑方,那景新.转动Timoshenko梁的动力学方程及频率分析 [J].应用力学学报,1996,13(4):119-123,171.ZOU J Q,LU Y F,NA J X.Dynamic equations of rotating Timoshenko beam and its frequency analysis [J].Chinese Journal of Applied Mechanics,1996,13(4):119-123,171.(in Chinese)

    • [6] 李彬,刘锦阳,洪嘉振.计及剪切变形的Timoshenko梁的刚-柔耦合动力学 [J].计算力学学报,2006,23(4):419-422.LI B,LIU J Y,HONG J Z.Coupling dynamics of Timoshenko beam with shear deformation [J].Chinese Journal of Computational Mechanics,2006,23(4):419-422.(in Chinese)

    • [7] 潘科琪,刘锦阳.计及剪切变形复合材料梁的刚/柔耦合动力学特性 [J].上海交通大学学报,2009,43(8):1293-1297.PAN K Q,LIU J Y.Rigid-flexible coupling dynamics of composite beam considering shear deformation [J].Journal of Shanghai Jiaotong University,2009,43(8):1293-1297.(in Chinese)

    • [8] 邓峰岩,和兴锁,张娟,等.旋转Timoshenko梁的动力学分析 [J].航空学报,2006,27(6):1092-1096.DENG F Y,HE X S,ZHANG J,et al.Dynamic analysis of rotating Timeshenko beams [J].Acta Aeronautica et Astronautica Sinica,2006,27(6):1092-1096.(in Chinese)

    • [9] ZHOU D,FANG J,WANG H,et al.Three-dimensional dynamics analysis of rotating functionally gradient beams based on timoshenko beam theory [J].International Journal of Applied Mechanics,2019,11(4):1950040.

    • [10] DAS D.Free vibration and buckling analyses of geometrically non-linear and shear-deformable FGM beam fixed to the inside of a rotating rim [J].Composite Structures,2017,179(1):628-645.

    • [11] 曹蕾蕾,裴建中,张学敏,等.功能梯度材料热传导问题的仿真 [J].计算机仿真,2012,29(8):387-390.CAO L L,PEI J Z,ZHANG X M,et al.Simulation method of steady-state heat conduction in functionally graded material [J].Computer Simulation,2012,29(8):387-390.(in Chinese)

    • [12] 高祥.考虑热效应的功能梯度材料梁的动力学建模与仿真[D].扬州:扬州大学,2021.GAO X.Dynamic modeling and simulation of functionally graded material beams with thermal effect[D].Yangzhou:Yangzhou University,2021.(in Chinese)

    • [13] 刘锦阳,袁瑞,洪嘉振.考虑热效应的柔性板的刚柔耦合动力学特性 [J].上海交通大学学报,2008,42(8):1226-1232,1237.LIU J Y,YUAN R,HONG J Z.The on rigid-flexible coupling dynamic performance for a rectangular plate considering thermal effect [J].Journal of Shanghai Jiaotong University,2008,42(8):1226-1232,1237.(in Chinese)

    • [14] 刘锦阳,潘科琪.考虑热效应的复合材料多体系统动力学研究 [J].动力学与控制学报,2009,7(1):9-13.LIU J Y,PAN K Q.Dynamic investigation on composite flexible multi-body system considering thermal effect [J].Journal of Dynamics and Control,2009,7(1):9-13.(in Chinese)

    • [15] 范纪华,陈立威,王明强,等.旋转中心刚体-FGM梁刚柔热耦合动力学特性研究 [J].力学学报,2019,51(6):1905-1917.FAN J H,CHEN L W,WANG M Q,et al.Research on dynamics of a rigid-flexible-thermal coupling rotating hub-FGM beam [J].Chinese Journal of Theoretical and Applied Mechanics,2019,51(6):1905-1917.(in Chinese)

    • [16] 黎亮,章定国,郭永彬.变温度场中刚柔耦合功能梯度梁系统的动力学特性研究 [J].振动工程学报,2017,30(1):9-19.LI L,ZHANG D G,GUO Y B.Dynamics of rigid-flexible coupling FGM beam systems in variable temperature fields [J].Journal of Vibration Engineering,2017,30(1):9-19.(in Chinese)

    • [17] Liu G R,Gu Y T.A point interpolation method [C].Proceedings of the 4th Asia-Pacific Conference on Computational Mechanics.1999:1009-1014.

    • [18] 杜超凡,章定国.基于无网格点插值法的旋转悬臂梁的动力学分析 [J].物理学报,2015,64(3):406-415.DU C F,ZHANG D G.A meshfree method based on point interpolation for dynamic analysis of rotating cantilever beams [J].Acta Physica Sinica,2015,64(3):406-415.(in Chinese)

    • [19] WANG J G,LIU G R.A point interpolation meshless method based on radial basis functions [J].International Journal for Numerical Methods in Engineering,2002,54(11):1623-1648.

    • [20] KANSA E J.Multiquadrics-A scattered data approximation scheme with application to computational fluid-dynamics-Ⅱ solutions to parabolic,hyperbolic and elliptic partial differential equations [J].Computers and Mathematics with Applications,1990,19(8-9):147-161.

    • [21] 杜超凡,章定国,洪嘉振.径向基点插值法在旋转柔性梁动力学中的应用 [J].力学学报,2015,47(2):279-288.DU C F,ZHANG D G,HONG J Z.A meshfree method based on radial point interpolation method for the dynamic analysis of rotating flexible beams [J].Chinese Journal of Theoretical and Applied Mechanics,2015,47(2):279-288.(in Chinese)

    • [22] 杨兴,刘仁伟,侯鹏,等.基于一阶剪切板理论的FGM板刚柔耦合动力学建模与仿真 [J].动力学与控制学报,2020,18(4):33-43.YANG X,LIU R W,HOU P,et al.Dynamic modeling and simulation of functionally graded materials plates based on first order shear plate theory [J].Journal of Dynamics and Control,2020,18(4):33-43.(in Chinese)

  • 参考文献

    • [1] KOIZUMI M.FGM activities in Japan.Composites Part B,1997,28(1-2):1-4.

    • [2] OH S Y,LIBRESCU L,SONG O.Thermoelastic modeling and vibration of functionally graded thin-walled rotating blades [J].AIAA Journal,2012,41(10):2051-2061.

    • [3] SONG O O.Spinning thin-walled beams made of functionally graded materials:modeling,vibration and instability [J].European Journal of Mechanics-A/Solids,2003,23(3):499-515.

    • [4] OH S Y,LIBRESCU L,SONG O.Vibration and instability of functionally graded circular cylindrical spinning thin-walled beams [J].Journal of Sound and Vibration,2005,285(4-5):1071-1091.

    • [5] 邹建奇,陆佑方,那景新.转动Timoshenko梁的动力学方程及频率分析 [J].应用力学学报,1996,13(4):119-123,171.ZOU J Q,LU Y F,NA J X.Dynamic equations of rotating Timoshenko beam and its frequency analysis [J].Chinese Journal of Applied Mechanics,1996,13(4):119-123,171.(in Chinese)

    • [6] 李彬,刘锦阳,洪嘉振.计及剪切变形的Timoshenko梁的刚-柔耦合动力学 [J].计算力学学报,2006,23(4):419-422.LI B,LIU J Y,HONG J Z.Coupling dynamics of Timoshenko beam with shear deformation [J].Chinese Journal of Computational Mechanics,2006,23(4):419-422.(in Chinese)

    • [7] 潘科琪,刘锦阳.计及剪切变形复合材料梁的刚/柔耦合动力学特性 [J].上海交通大学学报,2009,43(8):1293-1297.PAN K Q,LIU J Y.Rigid-flexible coupling dynamics of composite beam considering shear deformation [J].Journal of Shanghai Jiaotong University,2009,43(8):1293-1297.(in Chinese)

    • [8] 邓峰岩,和兴锁,张娟,等.旋转Timoshenko梁的动力学分析 [J].航空学报,2006,27(6):1092-1096.DENG F Y,HE X S,ZHANG J,et al.Dynamic analysis of rotating Timeshenko beams [J].Acta Aeronautica et Astronautica Sinica,2006,27(6):1092-1096.(in Chinese)

    • [9] ZHOU D,FANG J,WANG H,et al.Three-dimensional dynamics analysis of rotating functionally gradient beams based on timoshenko beam theory [J].International Journal of Applied Mechanics,2019,11(4):1950040.

    • [10] DAS D.Free vibration and buckling analyses of geometrically non-linear and shear-deformable FGM beam fixed to the inside of a rotating rim [J].Composite Structures,2017,179(1):628-645.

    • [11] 曹蕾蕾,裴建中,张学敏,等.功能梯度材料热传导问题的仿真 [J].计算机仿真,2012,29(8):387-390.CAO L L,PEI J Z,ZHANG X M,et al.Simulation method of steady-state heat conduction in functionally graded material [J].Computer Simulation,2012,29(8):387-390.(in Chinese)

    • [12] 高祥.考虑热效应的功能梯度材料梁的动力学建模与仿真[D].扬州:扬州大学,2021.GAO X.Dynamic modeling and simulation of functionally graded material beams with thermal effect[D].Yangzhou:Yangzhou University,2021.(in Chinese)

    • [13] 刘锦阳,袁瑞,洪嘉振.考虑热效应的柔性板的刚柔耦合动力学特性 [J].上海交通大学学报,2008,42(8):1226-1232,1237.LIU J Y,YUAN R,HONG J Z.The on rigid-flexible coupling dynamic performance for a rectangular plate considering thermal effect [J].Journal of Shanghai Jiaotong University,2008,42(8):1226-1232,1237.(in Chinese)

    • [14] 刘锦阳,潘科琪.考虑热效应的复合材料多体系统动力学研究 [J].动力学与控制学报,2009,7(1):9-13.LIU J Y,PAN K Q.Dynamic investigation on composite flexible multi-body system considering thermal effect [J].Journal of Dynamics and Control,2009,7(1):9-13.(in Chinese)

    • [15] 范纪华,陈立威,王明强,等.旋转中心刚体-FGM梁刚柔热耦合动力学特性研究 [J].力学学报,2019,51(6):1905-1917.FAN J H,CHEN L W,WANG M Q,et al.Research on dynamics of a rigid-flexible-thermal coupling rotating hub-FGM beam [J].Chinese Journal of Theoretical and Applied Mechanics,2019,51(6):1905-1917.(in Chinese)

    • [16] 黎亮,章定国,郭永彬.变温度场中刚柔耦合功能梯度梁系统的动力学特性研究 [J].振动工程学报,2017,30(1):9-19.LI L,ZHANG D G,GUO Y B.Dynamics of rigid-flexible coupling FGM beam systems in variable temperature fields [J].Journal of Vibration Engineering,2017,30(1):9-19.(in Chinese)

    • [17] Liu G R,Gu Y T.A point interpolation method [C].Proceedings of the 4th Asia-Pacific Conference on Computational Mechanics.1999:1009-1014.

    • [18] 杜超凡,章定国.基于无网格点插值法的旋转悬臂梁的动力学分析 [J].物理学报,2015,64(3):406-415.DU C F,ZHANG D G.A meshfree method based on point interpolation for dynamic analysis of rotating cantilever beams [J].Acta Physica Sinica,2015,64(3):406-415.(in Chinese)

    • [19] WANG J G,LIU G R.A point interpolation meshless method based on radial basis functions [J].International Journal for Numerical Methods in Engineering,2002,54(11):1623-1648.

    • [20] KANSA E J.Multiquadrics-A scattered data approximation scheme with application to computational fluid-dynamics-Ⅱ solutions to parabolic,hyperbolic and elliptic partial differential equations [J].Computers and Mathematics with Applications,1990,19(8-9):147-161.

    • [21] 杜超凡,章定国,洪嘉振.径向基点插值法在旋转柔性梁动力学中的应用 [J].力学学报,2015,47(2):279-288.DU C F,ZHANG D G,HONG J Z.A meshfree method based on radial point interpolation method for the dynamic analysis of rotating flexible beams [J].Chinese Journal of Theoretical and Applied Mechanics,2015,47(2):279-288.(in Chinese)

    • [22] 杨兴,刘仁伟,侯鹏,等.基于一阶剪切板理论的FGM板刚柔耦合动力学建模与仿真 [J].动力学与控制学报,2020,18(4):33-43.YANG X,LIU R W,HOU P,et al.Dynamic modeling and simulation of functionally graded materials plates based on first order shear plate theory [J].Journal of Dynamics and Control,2020,18(4):33-43.(in Chinese)

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