不同边界条件正交各向异性中厚板的振动与稳定分析

本文采用高阶剪切变形理论对正交各向异性中厚矩形板进行振动与稳定分析,数值计算采用样条有限点法,得出了六种不同边界条件矩形板的自振频率和屈曲载荷,并与相应的经典板理论的结果进行比较.结果说明横向剪切变形对复合材料层合板的影响与板的各向异性程度、板的宽厚比(b/h)、层合板的层数和板的支承条件有关,它随着层合板各向异性程度的增加而增加,随着层合板宽厚比的增加而逐渐消失.     

用高阶位移模式分析复合材料层合板的自由振动

建立一种新的高阶位移模式：分层假设复合材料层合板的位移场，利用各层间应力及位移的连续性条件，导出了作为整体的层合板控制微分方程。最后，采用这一高阶剪切理论来分析复合材料矩形层合板的自由振动。数值计算采用有限差分法，并编制了计算程序，计算得出了六种不同边界条件、不同铺层、不同宽厚比工况下的矩形层合板的自振频率。同经典理论解进行比较，可以看出本文方法简便易行，且精度较高，可以在微机上实用。     

中间弱层对层合板性能影响分析

对于夹胶玻璃等结构,由于中间胶层很弱,层合板结构的层间剪切效应占主导地位。此时经典层合板理论以及整体高阶剪切位移场理论所预测的结果可能导致很大的实际误差,应采用更加精细的力学模型来分析弱层的效应。本文建立了分层位移场假设下的浅柱面层合板静力计算模型以及自振周期计算模型,并同经典层合板理论计算结果对比,分析了中间层的剪切模量、弹性模量、层合板曲率半径对层间剪切效应的影响。计算结果表明:中间层的剪切模量对层合板的受力性能有着决定性的影响,相对来说中间层的弹性模量对层合板性能的影响不太显著;当中间层与面层的剪切模量比值小于0.2时,随着中间层剪切模量的减小,两个模型的计算误差急剧增大。     

复合材料层合板壳的非线性热动态响应分析

本文基于高阶剪切变形理论，考虑同天应变和横向剪切应变的影响，对受热复合材料层合板壳的非线性热动态响应进行分析，计及了转动惯量的影响，给出了通用性较好的Ｃ＾０类有限元公式，文中数值算同现有文献和三维有限元计算结果进行了比较，证明了本文方法的精确、有效性，文中还就层合板的边界条件、纵厚比及铺设角度对非线性热动态响应的影响进行了分析。     

基于逆复合二次径向基函数的对称复合材料层合板自由振动分析

利用逆复合二次径向基函数无网格配点法对Reddy的高阶剪切变形理论进行离散,预测了对称复合材料层合板的自由振动特性.将不同材料参数、几何尺寸和边界条件的层合板固有频率计算结果与相关文献中的结果进行对比,结果表明:逆复合二次径向基函数在对称复合材料层合板自由振动分析方面具有收敛性好及精度高等一系列优点.     

非对称铺层复合材料层合板的双稳态特性半解析研究

非对称铺层的复合材料层合板在存在热残余应力的情况下，具有双稳态性质．层合板的两个稳态之间仅需要一个适当的激励就可以互相转化，因此该结构在变体飞机上应用广泛．基于经典层合板理论，本文引入几何大变形建立了具有双稳态性质的复合材料层合板的能量泛函，提出了一个高阶的位移场函数，用瑞利里兹法推导出一组关于位移场函数系数的非线性方程组．结合牛顿迭代法和消元法求解非线性方程组，得到了层合板面外位移场．同时利用有限元软件ABAQUS，对复合材料层合板双稳态机理进行了数值模拟．选取了几组具有代表性的铺层进行计算，以有限元结果为基准，比较了本文的位移场结果与前人的结果，验证了高阶位移场函数的准确性．     

计入横向剪切变形时层合板位移差分解法

在考虑横向剪切变形对层合板弹性解的影响时，本文提出一种数值计算方法。由边界条件给出边界结点位移的表达式，根据薄板的经典理论和一阶横向剪切变形理论导出位移增量所满足的平衡微分方程，引用经典理论计算的横向剪力修正了荷载列阵。致使在较粗的网格划分时、宽广的层合板长厚比范围内，仍能得到与解析解颇为一致的数值解。     

带剪切型压电激励器的板的高阶剪切变形理论

利用压电材料固有的正，逆压电效应可以对结构变形和振动进行控制。与外加电场与极化方向平行于板厚度的压电材料的拉伸作动机制相比，外加电场与极化方向垂直的压电材料的剪切作动机制可以在作动器内产生较小的应力，从而降低作动器边界产生分层破坏的危险。本文对于压电材料的剪切作动机制进行研究，应用三阶剪切变形理论建立带剪切型压电激励器的智能层合板模型。采用哈密顿原理导出带剪切型压电激励器的层合板的控制方程。采用空间法得到了各种边界条件组合条件下板的解析解。数值算例对一三层板采用高阶和一阶剪切变形理论进行计算，结果表明两种理论所得的变形曲线很相似。但对于厚度剪切型激励器而言，由于激励器是引起板的剪切变形，而高阶剪切变形理论比一阶剪切变形理论能更好地反映结构的剪切应变能，因此高阶剪切变形理论可以提供板变形的更为精确的解。因此，对于厚度剪切型激励器，剪切变形理论的选取对于板变形结果的好坏有重要的作用。     

含界面脱粘压电复合材料层合板的非线性动力稳定性分析

基于Reddy提出的板高阶剪切变形简化理论,研究了含界面脱粘损伤压电复合材料层合板非线性动力稳定性问题.首先,建立了分层模型,推导了考虑几何非线性、阻尼效应、纵向惯性力和力-电耦合效应的Mathieu方程,并且给出了该方程解的解析表达式.其次,通过典型算例讨论了界面脱粘损伤以及反馈控制力对该层合板动力不稳定区域、纵向、横向共振频率和最大"牵引"深度的影响.由典型算例讨论可知:随着层合板界面脱粘损伤的扩大,其动力稳定性能逐渐减弱,其中在损伤较小时,反馈控制力对智能结构几乎没有影响;而在损伤比较大的情况下,反馈控制力将能有效地减少动力不稳定区域重合面积.     

基于新修正偶应力理论的Mindlin层合板稳定性分析

基于新的各向异性修正偶应力理论提出一个Mindlin复合材料层合板稳定性模型。该理论包含纤维和基体两个不同的材料长度尺度参数。不同于忽略横向剪切应力的修正偶应力Kirchhoff薄板理论,Mindlin层合板考虑横向剪切变形引入两个转角变量。进一步建立了只含一个材料细观参数的偶应力Mindlin层合板工程理论的稳定性模型。计算了正交铺设简支方板Mindlin层合板的临界载荷。计算结果表明该模型可以用于分析细观尺度层合板稳定性的尺寸效应。     

Six-variable geometrical nonlinear laminated theory for large deformation

A six-variable geometrical nonlinear shear deformation laminated theory is presented by which normal stress and strain distribution can be calculated. By considering some affective factors that were neglected under the finite deformation condition, an improved von Karman geometrical nonlinear deformation-strain relation is used for large deformation analysis. After analyzing the bending problem of laminated plates, and comparing it with 3-D elasticity solutions and J. N. Reddy five-variable simple higher-order shear deformation laminated theory, we can conclude that a satisfactory calculation precision has been achieved, which shows that it is especially suitable for the calculation in the condition of large deformation and the laminated thick plate analysis.     

SMA纤维混杂层合梁的材料阻尼

研究一类由形状记忆合金（SMA）和普通纤维混杂而成的层合梁的阻尼特性,基于最大应变能理论提出SAM混杂层合梁的等效材料阻尼预测的数学模型,其中,单层材料的弹性性能和阻尼性能分别采用多胞模型及其阻尼细观力学分析模型确定,利用正交各向异性层合梁的铁木辛柯理论分析梁的变形,通过数值算例分析了SMA含量,纤维铺设角对梁的等效阻尼比的影响。     

POSTBUCKLING OF PRESSURE-LOADED SHEAR DEFORMABLE LAMINATED CYLINDRICAL PANELS

IntroductionInrecentyears,fiber_reinforcedcompositelaminatedpanelshavebeenwidelyusedintheaerospace,marine ,automobileandotherengineeringindustries .Theproblemofbucklingandpostbucklingofcylindricalpanelsunderaxialcompressionortorsionhasbeenextensivelystudied .Incontrast,theliteratureoncylindricalpanelsunderpressureloadingisrelativelyspares.Thesestudiesincludealinearbucklinganalysis (Singeretal.[1]) ,anonlinearbucklinganalysi(YamadaandCroll[2 ]) ,anelastoplasticbucklinganalysisusingreducedstif…     

Analysis of composite laminated plates

In the static and dynamic analysis of composite laminates, a theory for the laminated plates is presented in this paper. Because the deflection W_b which is caused by the classical bending deformation and the deflection W₅ which is caused by the shear deformation are divided from the total deflection W in the theory, this makes it easy to solve the governing equations. In addition, this theory is convenient for the discussion and analysis of the effects of transverse shear deformations on bendings, vibrations and stabilities of laminated plates.     

具损伤压电智能层合板的动力分析

基于应变能等效原理、高阶剪切变形理论和Hamilton变分原理,考虑复合材料铺设层内的损伤效应,建立了具损伤压电智能层合板的运动控制方程,并运用Galerkin方法进行求解.数值算例中,讨论了损伤效应、厚跨比及压电层厚度与层合板总厚度之比对四边简支压电智能层合板自由振动频率的影响和外部控制电压对其动力响应的影响.     

Analysis of laminated glass beams for photovoltaic applications

Laminated glass beams and plates are widely used in glazing and photovoltaic applications. One feature of these structures is a relatively thin and compliant polymeric layer for embedding solar cells. Proper design of photovoltaic glass modules requires an analysis of transverse shear strain distribution in polymeric encapsulant. In this paper a three layered beam with glass skins and a polymeric core is applied as a model structure to evaluate the mechanical properties. Robust relationships between the maximum deflection, the transverse shear strain of the core layer and the applied force in a three-point-bending test of laminated glass beam samples are derived. The first order shear deformation beam theory and a layer-wise type beam theory are applied. An expression for the transverse shear stiffness of the laminated glass beam is presented. The results for the maximum deflection are compared with the results discussed in the literature. Furthermore, a three-dimensional finite element analysis is performed to verify the applied beam theories. Three-point-bending tests for laminated glass beams with core layers from different polymeric materials are performed. The experimental data for the maximum deflection are compared with the derived expressions.     

Sound transmission from stiffened double laminated composite plates

An analytical model is developed to investigate the sound transmission loss from orthogonally rib-stiffened double laminated composite plates structure under a plane sound wave excitation, in which first order shear deformation theory is presented for laminated composite plates. By using the space harmonic approach and virtual work principle, the sound transmission loss is described analytically. The validity and feasibility of the model are verified by comparing the present theoretical predictions with numerical results published previously. The influences of structure geometrical parameters on sound transmission loss are subsequently presented. Through numerical results, it can be concluded that the proposed analytical model is accurate and simple in solving the vibroacoustic behavior of an orthogonally rib-stiffened double laminated composite plates.     

Free vibration analysis of third-order shear deformable composite beams using dynamic stiffness method

The dynamic stiffness method is introduced to investigate the free vibration of laminated composite beams based on a third-order shear deformation theory which accounts for parabolic distribution of the transverse shear strain through the thickness of the beam. The exact dynamic stiffness matrix is found directly from the analytical solutions of the basic governing differential equations of motion. The Poisson effect, shear deformation, rotary inertia, in-plane deformation are considered in the analysis. Application of the derived dynamic stiffness matrix to several particular laminated beams is discussed. The influences of Poisson effect, material anisotropy, slenderness and end condition on the natural frequencies of the beams are investigated. The numerical results are compared with the existing solutions in literature whenever possible to demonstrate and validate the present method.     

弱粘结的斜交铺设层合圆柱壳的柱形弯曲

导出了两端简文的具有弱粘结界面的任意斜交铺设层合圆柱壳柱形弯曲问题的一个精确弹性理论解。分析中采用线性弹簧模型来表征界面的弱粘结特性。引进新的物理量改写了基本方程,导出了对应的状态空间列式,并利用变量替换技术将该状态方程转换成常系数状态方程,从而方便求解。最后给出了数值算例,并讨论了弱界面的影响。