共查询到20条相似文献,搜索用时 15 毫秒
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沈惠申 《应用数学和力学(英文版)》1998,19(5):411-423
1.IntroductionStiffenedcylindricalshellsarewidelyusedinmanytypesofstructures.Inpracticetheyoftensubjecttovarioustypesofcombinedthermalandmechanicalloadingandmayhavesignificantandunavoidableinitialgeometricalimperfections.Therefore,thepostbucklingbehaviorofimperfectstiITenedcylindricalshellsundercombinedexternalpress.ureandthermalloadingmustbewellunderstood.Manypostbucklingstudieshavebeenmadetbrstiffenedcylindricalshellsunderpureaxialcompression,uniformexternalpressureortheircombinations,where… 相似文献
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A compressive postbuckling analysis is presented for a laminated cylindrical shell with piezoelectric actuators subjected to the combined action of mechanical, electric and thermal loads. The temperature field considered is assumed to be a uniform distribution over the shell surface and through the shell thickness, and the electric field is assumed to be the transverse component EZ only. The material properties are assumed to be independent of the temperature and the electric field. The governing equations are based on the classical shell theory with von Kármán–Donnell-type kinematic nonlinearity. The nonlinear prebuckling deformations and initial geometric imperfections of the shell are both taken into account. A boundary layer theory of shell buckling, which includes the effects of nonlinear prebuckling deformations, large deflections in the postbuckling range, and initial geometric imperfections of the shell, is extended to the case of hybrid laminated cylindrical shells. A singular perturbation technique is employed to determine the buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the compressive postbuckling behavior of perfect and imperfect, cross-ply laminated cylindrical thin shells with fully covered or embedded piezoelectric actuators under different sets of thermal and electric loading conditions. The effects played by temperature rise, applied voltage, shell geometric parameter, stacking sequence, as well as initial geometric imperfections are studied. 相似文献
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沈惠申 《应用数学和力学(英文版)》2003,24(4):402-413
IntroductionInrecentyears,fiber_reinforcedcompositelaminatedpanelshavebeenwidelyusedintheaerospace,marine ,automobileandotherengineeringindustries .Theproblemofbucklingandpostbucklingofcylindricalpanelsunderaxialcompressionortorsionhasbeenextensivelystudied .Incontrast,theliteratureoncylindricalpanelsunderpressureloadingisrelativelyspares.Thesestudiesincludealinearbucklinganalysis (Singeretal.[1]) ,anonlinearbucklinganalysi(YamadaandCroll[2 ]) ,anelastoplasticbucklinganalysisusingreducedstif… 相似文献
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将Koiter理论和奇异摄动理论中的边界层法相结合处理加筋圆柱壳无因次化非线性边界层型Karman-Donnel方程由分支点和边界层导致的双重奇异性,提出外压加筋圆柱壳总体屈曲Koiter—边界层奇异摄动法。从摄动意义上分析边界条件,前屈曲非线性和初始几何缺陷对外压加筋圆柱壳屈曲载荷的影响。算例表明,本方法具有良好的计算效率和计算精度,与数值解相比更能揭示内在影响规律。 相似文献
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加权残值法分析轴压圆柱薄壳后屈曲问题 总被引:1,自引:0,他引:1
本文首次应用了样条配点法分析了受到轴向压力的圆柱形薄壳的后屈问题,壳体的方程是L.H.Donnell的非线性正交异性圆柱形壳体方程,壳体的挠度试函数及应力函数试函数都是于轴向用了五次B样条函数基函数,周向用余弦函数。计算模型是周向为半个波长的壳块,可适应后屈曲实验变形跳跃现象。非线性代数方程组用了Newton—Rophson迭代法求解。由此所得的理论上的后屈曲曲线与国外近代实验相符。 相似文献
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Thermo-piezoelectric effects on the postbuckling of axially-loaded hybrid laminated cylindrical panels 总被引:1,自引:0,他引:1
沈惠申 《应用数学和力学(英文版)》2004,25(1):24-38
IntroductionCompositelaminatedcylindricalpanelhasbeenusedextensivelyasastructuralconfiguration,mainlyintheaerospaceindustry .Oneoftherecentadvancesinmaterialandstructuralengineeringisinthefieldofsmartstructureswhichincorporatesadaptivematerials.Bytakingadvantageofthedirectandconversepiezoelectriceffects,piezoelectriccompositestructurescancombinethetraditionalperformanceadvantagesofcompositelaminatesalongwiththeinherentcapabilityofpiezoelectricmaterialstoadapttotheircurrentenvironment.Therefore… 相似文献
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Buckling and postbuckling behaviors of perfect and imperfect,stringer andorthotropically stiffened cylindrical shells have been studied under axial compression.Based on the boundary layer theory for the buckling of thin elastic shells suggested in ref.[1],a theoretical analysis is presented.The effects of material properties of stiffeners andskin,which are made of different materials,on the buckling load and postbuckling behaviorof stiffened cylindrical shells have also been discussed. 相似文献
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袁镒吾 《应用数学和力学(英文版)》1985,6(9):871-877
This paper presents a step-by-step approximating method to obtain the analyticalsolutions of the differential equations for the self-similar problems of viscous fluid flow(1.1-1.4).Prosnak(1969)obtained solutions of these equations by using a small paremetermethod,but he reduced the governing equations to the linear differential equations withconstant coefficients. 相似文献
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IntroductionWhencompositecylindricalshellsareundertheactionofdynamicloading ,theymayfallindynamicbucklingordynamicinstability .Ifthedynamicloadissuddenlyapplied ,oritischanginginstantaneously ,suchasimpulsiveloading ,then ,dynamicbucklingwillhappenforthesh… 相似文献
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变角度纤维复合材料的纤维方向角可沿铺层面内连续变化,因此相应结构的性能具有更高的设计灵活性和更大的优化空间.本文假设纤维方向角沿圆柱壳的轴向呈正弦函数变化,对变角度纤维复合材料圆柱壳在两端简支边界条件下的轴压屈曲问题进行研究.基于Donnell经典壳体理论,推导变角度纤维复合材料圆柱壳的前屈曲控制方程并运用伽辽金法进行求解,然后采用瑞利里兹法求解屈曲问题.通过和现有文献及有限元数值结果的对比,验证了本文模型的收敛性和正确性,通过数值算例分析了纤维起始角和终止角的变化对圆柱壳的屈曲临界荷载的影响.本文的研究结果可为变角度纤维复合材料圆柱壳的分析和设计提供一定的参考. 相似文献
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Buckling and postbuckling behavior of antisymmetrically angle-ply laminated composite plates 总被引:1,自引:0,他引:1
沈惠申 《应用数学和力学(英文版)》1990,11(12):1155-1165
The buckling and postbuckling behaviors of perfect and imperfect antisymmetricallyangle-ply laminated composite plates under uniaxial compression have been studied byperturbation technique which takes deflection as its perturbation parameter.In this paper,the effects of in-plane boundary conditions,angles,total number oflayers and initial geometric imperfection on the postbuckling behavior of laminated plateshave been discussed. 相似文献
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Cylindrical shells produced by single-layer or cross winding are analyzed for stability. An approximate analytical solution
is proposed. It allows evaluating the effect of an unbalanced laminate on the critical values of the axial load, intensity
of external pressure, and shear forces. It is shown that the effect of imbalance weakens with increase in the number of laminas.
In each specific case, the number of laminas at which the material can be considered orthotropic is determined
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Translated from Prikladnaya Mekhanika, Vol. 41, No. 6, pp. 113–120, June 2005. 相似文献
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The stability of fiber-reinforced cylindrical shells under torsion is analyzed in the case where the principal directions
of elasticity in the layers do not coincide with the coordinate directions. The solution to the linearized equations of the
technical theory of anisotropic shells is obtained in the form of trigonometric series. It is shown that for some reinforcement
configurations the critical loads may depend on the direction of the torsional moment. It is also established that the minimum
(in absolute value) eigenvalue does not always correspond to the critical load. This fact should be taken into account not
only in the case of torsion but also in more complicated cases of loading
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Translated from Prikladnaya Mekhanika, Vol. 41, No. 10, pp. 100–107, October 2005. 相似文献
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轴向应力波作用下圆柱壳弹性轴对称动力失稳有限元特征值分析 总被引:1,自引:0,他引:1
本文运用有限元特征值分析方法对应力波作用下圆柱壳弹性轴对称动力失稳问题进行了研究。基于应力波理论和相邻平衡准则导出了圆柱壳轴对称动力失稳时的有限元特征方程,在此方程中考虑了应力波效应及横向惯性效应,把圆柱壳弹性动力失稳问题归结为特征值问题。通过引入圆柱壳动力失稳时的波前约束条件实现了此类问题的有限元特征值解法。计算结果揭示了圆柱壳弹性轴对称动力屈曲变形发展的机理,以及轴向应力波和屈曲变形的相互作用规律。 相似文献
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在径向载荷和轴向冲击联合作用下的圆柱壳塑性稳定性分析 总被引:3,自引:0,他引:3
对有径向载荷的圆柱壳,受轴向冲击时塑性失稳的临界速度进行理论分析。分析结果与实验值相吻合,并给出一般的规律,它也适用于无径向载荷的情况。 相似文献
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The paper sets forth a technique, based on the Kirchhoff–Love theory of shells, for solving stability problems for thin-walled laminated shells of revolution made of an anisotropic material with one plane of elastic symmetry. The resolving system of differential equations is of the 16th order since the symmetric and asymmetric buckling modes are coupled. The results from a stability analysis of cylindrical shells made of carbon plastics and subjected to compression are analyzed against the angle of the principal directions of elasticity. The influence of boundary conditions is studied. The error due to neglecting the coupling of buckling modes is estimated 相似文献
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A method is proposed for determining the thermoelastoplastic stress–strain state of laminated shells of revolution, made of isotropic and transversely isotropic materials, under axisymmetric loading. The method is based on the Kirchhoff–Love hypotheses for a layer stack, the theory of deformation along paths of small curvature for isotropic materials, and Hill's flow theory with isotropic hardening for transversely isotropic materials. The loading history is accounted for. The problem is solved by the method of successive approximations. Numerical examples are given 相似文献