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复合材料层合开顶扁球壳的非线性动态屈曲 总被引:10,自引:0,他引:10
研究了复合材料层合开顶扁球壳的非线性动态屈曲问题。建立了对称层合圆柱正交异性开顶扁球壳考虑横向剪切的非线性振动微分方程,根据突变理论建立了该壳体动态屈曲的突变模型,得到了动态屈曲的临界方程。 相似文献
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波纹壳是传感器弹性元件的一类重要形式,也是精密仪器仪表弹性元件中的一类重要形式。由于波纹壳形状复杂、参数众多、厚度薄,对其进行非线性分析非常重要同时也是十分困难的。本文考虑一种在传感器弹性元件中有重要应用价值的正弦波纹浅球壳体,将这种壳体视为结构上的圆柱正交异性扁球壳,根据Andryewa的思想,分别得到了正弦波纹壳径向、环向在拉伸、弯曲下的等价的四个各向异性参数;建立了正弦波纹扁球壳的非线性强迫振动微分方程;得到了正弦波纹扁球壳非线性强迫振动的共振周期解及幅频特性曲线。 相似文献
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本文首先借助斜坐标系和阶跃函数,建立了多抛物面组合扁壳结构的微分方程,然后用扁壳非线性理论和辽金法,导出了这种壳面结构非线性分析的计算公式。 相似文献
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爆炸冲击下复合材料层合扁球壳的动力屈曲 总被引:1,自引:0,他引:1
研究计及横向剪切的复合材料层合扁球壳在爆炸冲击载荷作用下的非线性轴对称动力屈曲问题。通过在复合材料层合扁球壳非线性稳定性的基本方程中增加横向转动惯量项并引入R.H.Cole理论的爆炸冲击力,得到爆炸冲击下复合材料层合扁球壳的动力控制方程,应用Galerkin方法得到用顶点挠度表达的爆炸冲击动力响应方程,并采用Runge-Kutta方法进行数值求解,采用Budiansky-Roth准则确定冲击屈曲的临界载荷,讨论了壳体几何尺寸对复合材料层合扁球壳冲击屈曲的影响;数值算例表明,此方法是可行的。 相似文献
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本文从扁球壳的积分方程组出发,通过新定义的残差表达式,用权余法详细地研究了扁球壳轴对称非线性弯曲和稳定问题.通过数值计算可以看出,本方法应用方便,精确可靠. 相似文献
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壳体结构非线性分析的扁壳有限元法 总被引:1,自引:1,他引:0
用单位纵横向曲条条带法构造了扁壳单元的空间位移模式,依据拖带坐标描述去S-R分解定理,志出扁壳结构几何非线性分析的有限单元U.C.(updated co-moving coordinate)列式,算例表明,该计算方法精度高,收敛性好。 相似文献
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本文利用渐近迭代法获得了边界弹性支撑的功能梯度扁球壳的非线性屈曲问题的理论解.假设材料组分体积分数沿壳体厚度方向呈sigmoid幂函数变化,边界上考虑一般的弹性支撑约束.基于经典的薄壳理论和几何非线性关系,导出了S型功能梯度扁球壳的非线性屈曲问题的控制方程.采用渐近迭代法通过两次迭代得到了无量纲挠度和均布荷载之间的非线性特征关系.通过与已有有限元方法和其他数值方法的结果对比,验证了本文解的有效性和高精度.同时,通过计算阐述了缺陷因子、材料参数、边界约束系数及特征几何参数对壳体临界屈曲荷载的影响. 相似文献
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Nonlinear dynamic buckling of symmetrically laminated cylindrically orthotropic shallow spherical shells 总被引:9,自引:0,他引:9
Summary In this paper, a model of cusped catastrophe at nonlinear dynamic buckling of a symmetrically laminated cylindrically orthotropic
shallow spherical shell is presented. The shell is subjected to an axisymmetrical load. Effects of transverse shear are taken
into account. Effects of the shear modulus, geometry and parameters of the material on the nonlinear dynamic buckling are
discussed.
Received 2 April 1997; accepted for publication 27 November 1997 相似文献
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Based on the variational equation of the nonlinear bending theory of doubledeck reticulated shallow shells, equations of large deflection and boundary conditions for a double-deck reticulated circular shallow spherical shell under a uniformly distributed pressure are derived by using coordinate transformation means and the principle of stationary complementary energy. The characteristic relationship and critical buckling pressure for the shell with two types of boundary conditions are obtained by taking the modified iteration method. Effects of geometrical parameters on the buckling behavior are also discussed. 相似文献
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网格扁壳结构的非线性弯曲与稳定问题研究 总被引:7,自引:0,他引:7
本文利用作者分析得到的矩形网格扁壳结构的非线性控制方程,采用双重Fourier级数求解了该类结构的非线性问题。推导得到了外载与结构(中心)节点横向位移之间的三次非线性关系式。并作了算例分析,给出了结构产生失稳跳跃的条件。 相似文献
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This paper deals with nonlinear free vibration of reticulated shallow spherical shells taking into account the effect of transverse shear deformation. The shell is formed by beam members placed in two orthogonal directions. The nondimensional fundamental governing equations in terms of the deflection, rotational angle, and force function are presented, and the solution for the nonlinear free frequency is derived by using the asymptotic iteration method. The asymptotic solution can be used readily to perform the parameter analysis of such space structures with numerous geometrical and material parameters. Numerical examples are given to illustrate the characteristic amplitude-frequency relation and softening and hardening nonlinear behaviors as well as the effect of transverse shear on the linear and nonlinear frequencies of reticulated shells and plates. 相似文献
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Nonlinear static and dynamic analysis for laminated,annular, spherical caps of moderate thickness 总被引:1,自引:0,他引:1
Based on Timoshenko-Mindlin kinematic hypothesis, the shallow shell theory is extended to include the transverse shear deformation for the nonlinear axisymmetric dynamic analysis of the symmetric cross-ply shallow spherical shell. Using the orthogonal point collocation method and the Newmark scheme, an iterative solution is formulated. The numerical results for the nonlinear static and dynamic responses and dynamic buckling of these shallow spherical shells with circular holes under uniformly distributed static or dynamic normal impact loads are presented and compared with available data. 相似文献
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George J. Simitses Charles M. Blackmon 《International Journal of Solids and Structures》1975,11(9):1035-1049
The problem of snap-through buckling of a clamped, eccentrically stiffened shallow spherical cap is considered under quasi-statically applied uniform pressure and a special case of dynamically applied uniform pressure. This dynamic case is the constant load infinite duration case (step time-function) and it represents an extreme case of blast loading-large decay time, small decay rate.The analysis is based on the nonlinear shallow shell equations under the assumption of axisymmetric deformations and linear stress-strain laws. The eccentric stiff eners are disposed orthogonally along directions of principal curvature in such a way that the smeared mass, and extensional and flexural stiffnesses are constant. The stiffeners are also taken to be one-sided with constant eccentricity, and the stiffener-shell connection is assumed to be monolithic.The method developed in an earlier paper is employed. In this method, critical pressures are associated with characteristics of the total potential surface in the configuration space of the generalized coordinates.In addition, buckling of the complete thin eccentrically stiffened spherical shell under uniform quasi-statically applied pressure is considered, and these results are used to check the numerical answers. The complete spherical shell is stiffened in the same manner as the shallow cap.The results are presented in graphical form as load parameter vs initial rise parameter. Geometric configurations corresponding to isotropic, lightly stiffened, moderately stiffened and heavily stiffened geometries are considered. By lightly stiffened geometry one means that most of the extensional stiffness is provided by the thin shell. A computer program was written to solve for critical pressures. The Georgia Tech Univac 1108 high speed digital computer was used for this purpose. 相似文献
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The nonlinear thermal buckling of symmetrically laminated cylindrically orthotropic shallow spherical shell under temperature field and uniform pressure including transverse shear is studied. Also the analytic formulas for determining the critical buckling loads under different temperature fields are obtained by using the modified iteration method. The effect of transverse shear deformation and different temperature fields on critical buckling load is discussed. 相似文献
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IntroductionDouble_deckreticulatedshellsasamainformoflargespacestructures,arewidelyusedincivilengineeringandmanyotherfields[1,2 ].Oneofthemisthediagonalsquarepyramidreticulatedshallowshell.Theshellconsistsofreversesquarepyramidswhosevertexesarelinkedbylo… 相似文献