共查询到20条相似文献,搜索用时 15 毫秒
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《International Journal of Solids and Structures》2006,43(16):4810-4829
Here, the nonlinear thermo-elastic buckling/post-buckling characteristics of laminated circular conical–cylindrical/conical–cylindrical–conical joined shells subjected to uniform temperature rise are studied employing semi-analytical finite element approach. The nonlinear governing equations, considering geometric nonlinearity based on von Karman’s assumption for moderately large deformation, are solved using Newton–Raphson iteration procedure coupled with displacement control method to trace the pre-buckling/post-buckling equilibrium path. The presence of asymmetric perturbation in the form of small magnitude load spatially proportional to the linear buckling mode shape is assumed to initiate the bifurcation of the shell deformation. The study is carried out to highlight the influences of semi-cone angle, material properties and number of circumferential waves on the nonlinear thermo-elastic response of the different joined shell systems. 相似文献
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Giles Hunt 《Nonlinear dynamics》2006,43(1-2):29-46
A personal overview of the buckling process is given, based on more than 30 years research experience. A fundamental distinction
is drawn between structures that tend to distribute their pattern of buckling over the entire available length, and those
that favour limiting it to a localized portion. Difficulties are compounded by the fact that localized solutions typically
are shadowed by distributed counterparts. The difference is found to depend primarily on the stability of the system at the
point of buckling. When an unstable localized form shows a tendency to restabilize, a pattern known as cellular buckling can
develop, taking place sequentially in both space and time. The paper focuses particularly on the buckling of the axially-compressed
cylindrical shell, and shows how the circumferential periodicity coupled with axial localization has special but hidden characteristics.
In particular, the circumferential wavenumber is picked at an early stage of buckling and remains locked, while localization
in the axial sense permits extensive change to the post-buckling shape. 相似文献
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An analytical method is suggested to analyze the plastic post-buckling behavior under impulsive loading. The fundamental equation
of motion of a cylindrical shell is taken as an example to explain the main concept and procedure. The axial and the radial
displacements are decoupled by an approximate scheme, so that only one non-linear equation for the radial buckling displacement
is to be solved. By expanding it in terms of an amplitude measure as a time variable, we may get the post-buckling behavior
in the form of a series solution. The post-buckling behavior of a rectangular plate used as a special case of cylindrical
shell is discussed. 相似文献
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Meccanica - Thermo-mechanical buckling and post-buckling analysis of arbitrary, smooth and folded shells with different boundary conditions are investigated. A pure displacement-and-theory-based... 相似文献
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In this paper, investigation on buckling and post-buckling behaviors of a laminated cylindrical shell of functionally graded material (FGM) with the piezoelectric fiber reinforced composite (PFRC) actuators subjected to thermal and axial compressed loads is presented. Based on the Donnell assumptions, the material properties of the FGM layer vary smoothly through the laminated cylindrical shell thickness according to a power law distribution of the volume fraction of constituent materials. In the present study, a numerical procedure for the laminated cylindrical shell is used based on the Ritz energy method and the nonlinear strain–displacement relations. Some useful discussion and numerical examples are presented to show various effects of temperature field, volume fraction and geometric parameters on the buckling and post-buckling behaviors of the laminated cylindrical shell with PFRC. 相似文献
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The large-deflection analysis and post-buckling behavior of laterally braced or unbraced slender beam-columns of symmetrical cross section subjected to end loads (forces and moments) with both ends partially restrained against rotation, including the effects of out-of-plumbness, are developed in a classical manner. The classical theory of the “Elastica” and the corresponding elliptical functions utilized herein are those presented previously by Aristizabal-Ochoa [1]. The proposed method can be used in the large-deflection analysis and post-buckling behavior of elastic slender beam-columns with rigid, semi-rigid, and simple flexural connections at both ends including linear and non-linear inelastic connections like those that suffer from flexural degradation (such as flexural cracking and elasto-plastic connections) or flexural stiffening. Only bending strains are considered in the proposed analysis. Results from the proposed method are theoretically exact from small to very large curvatures and transverse and longitudinal displacements for laterally braced or unbraced slender beam-columns under bending caused by end loads. The large-deflection analysis and post-buckling behavior of slender beam-columns with both supports partially restrained against rotation and with sway inhibited or uninhibited are complex problems requiring the simultaneous solution of two coupled non-linear equations with elliptical integrals whose unknowns are the limits of the integrals. The validity of the proposed method and equations are verified against solutions available in the technical literature. Three comprehensive examples are included that show the effects of linear and non-linear connections at both ends on the large-deflection analysis and post-buckling behavior of slender beam-columns. 相似文献
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Shape memory polymers (SMPs) can have a large frozen strain but with a very small recovery stiffness in comparison with shape
memory metals or ceramics. To provide more deployable stresses for the application of actuators, sandwich beams consisting
of a SMP core and two thin metallic skins were considered. The packaging behaviors of two types of SMP sandwich beams, aluminum/SMP/aluminum
and steel/SMP/steel, were discussed. Due to the high compliance of SMP core on packaging condition that the testing temperature
is above the activation temperature of the material, buckling and post-buckling are the essential deformation mechanisms of
SMP sandwich beams under bending. Theoretical solutions were derived in studying such non-linear behaviors, including the
initiation of critical buckling, post-buckling response, and final failure modes. Systematic parameter’s analyses, e.g., buckling
half-wavelength, amplitude, location of the neutral-strain surface in different packaging curvatures, were also presented. 相似文献
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The buckling and initial postbuckling behavior of clamped shallow spherical sandwich shells with dissimilar face sheets under a uniform pressure is studied. The numerical results show that the buckling and initial post-buckling behavior of clamped shallow spherical sandwich shells with dissimilar face sheets is similar to that of the corresponding homogeneous shell. 相似文献
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受圆形表面单面约束的点锚固圆环热屈曲分析 总被引:1,自引:0,他引:1
应用W.T.Koiter的初始后屈曲理论,研究了受圆形混凝土表面单面约束的点锚固圆环的热屈曲问题,根据混凝土容器壁的几何约束条件,假设了圆环的合理屈曲模状,得出了圆环在两锚固点之间发生屈曲的临界温度,并研究了其后屈曲性态和缺陷敏感性。结果表明,临界点和后屈曲路径的平衡均为稳定的,圆环对于与屈曲模态形状相同的缺陷是不敏感的。 相似文献
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D. KaragiozovaNorman Jones 《International Journal of Non》2002,37(7):1223-1238
Some characteristic features of the dynamic inelastic buckling behaviour of cylindrical shells subjected to axial impact loads are discussed. It is shown that the material properties and their approximations in the plastic range influence the initial instability pattern and the final buckling shape of a shell having a given geometry. The phenomena of dynamic plastic buckling (when the entire length of a cylindrical shell wrinkles before the development of large radial displacements) and dynamic progressive buckling (when the folds in a cylindrical shell form sequentially) are analysed from the viewpoint of stress wave propagation resulting from an axial impact. It is shown that a high velocity impact causes an instantaneously applied load, with a maximum value at t=0 and whether or not this load causes an inelastic collapse depends on the magnitude of the initial kinetic energy. 相似文献
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在大位移和扭转的前提下,通过一中等弯曲扭转的位移场描述了薄壁箱形梁在偏心载荷作用下的静稳定性问题.该非线性公式可用于分析简支薄壁箱形梁在不同载荷作用下的屈曲和后屈曲行为.采用伽辽金方法将非线性微分系统离散,并通过牛顿-拉普森增量迭代法求解得代数方程组.数值计算结果表明,当前屈曲位移不可忽略时,经典的横向屈曲预测是保守的... 相似文献
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M. Shariyat 《International Journal of Solids and Structures》2008,45(9):2598-2612
FGM components are constructed to sustain high temperature gradients. There are many applications where the FGM components are vulnerable to transient thermal shocks. If a component is already under compressive external loads (e.g. under a combination of axial compression and external pressure), the mentioned thermal shocks will cause the component to exhibit dynamic behavior and in some cases may lead to buckling. On the other hand, a preheated FGM component may undergo dynamic mechanical loads. Only static thermal buckling investigations were developed so far for the FGM shells. In the present paper, dynamic buckling of a pre-stressed, suddenly heated imperfect FGM cylindrical shell and dynamic buckling of a mechanically loaded imperfect FGM cylindrical shell in thermal environment, with temperature-dependent properties are presented. The general form of Green’s strain tensor in curvilinear coordinates and a high order shell theory proposed already by the author are used. Instead of using semi-analytical solutions that rely on the validity of the separation of variables concept, the complicated nonlinear governing equations are solved using the finite element method. Buckling load is detected by a modified Budiansky criterion proposed by the author. The effects of temperature-dependency of the material properties, volume fraction index, load combination, and initial geometric imperfections on the thermo-mechanical post-buckling behavior of a shell with two constituent materials are evaluated. The results reveal that the volume fraction index and especially, the differences between the thermal stresses created in the outer and the inner surfaces may change the buckling behavior. Furthermore, temperature gradient and initial imperfections have less effect on buckling of a shell subjected to a pure external pressure. 相似文献
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ABSTRACT The post-buckling behavior of ring-stiffened cylinders subjected to lateral pressure is studied theoretically and experimentally. The theoretical analysis uses the energy method and terms of up to and including fourth order of the buckling displacements are considered. The results of experiments on ten machined ring-stiffened cylinders subjected to lateral pressure and used to verify the theoretical analysis. The theory shows the post-buckling behavior to be stable-symmetric for both the shell and general instability modes. The experimental results are in reasonable agreement with the theory, although they indicate, in general, a lower post-buckling stiffness. For the range of parameters considered, no instability or imperfection sensitivity is found in either the theoretical or the experimental studies. 相似文献
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含多个分层复合材料层合板后屈曲性态研究 总被引:5,自引:1,他引:4
基于Mindlin假定下的大变形板/壳理论,采用参考面单元和虚拟杆单元相结合的非线性有限元方法,建立了分析含多个穿透分层损伤层合板后屈曲行为的有限元计算模型,并给出了考虑接触后非线性屈曲方程的迭代算法,从而研究考虑层间接触效应的多分层层合板的后屈曲性态。文中着重讨论了分层的深度、数目和尺寸对含多分层合板后屈曲性态的影响。大量数值分析结果证明了该模型的有效性,并且得到了一些对层合板结构设计和对含分层损伤层合板评估有益的结论。 相似文献
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J. Wu Q.H. Cheng B. Liu Y.W. Zhang W.B. Lu K.C. Hwang 《Journal of the mechanics and physics of solids》2012,60(5):803-826
Via the energy-based analytical and numerical methods, this paper studies the pre- and post-buckling compression behaviors of concentric multi-walled cylindrical shells filled with low-shear-modulus (or fluid like) materials, which are widely observed in biological composites. It is found that if the bulk modulus of the filled materials is on the same order of (or larger than) the Young's modulus of the shell, the axial compression resistance in the post-buckling stage can be significantly improved. In specific, the tangent stiffness increases quickly with the increase of the compression strain, and finally may become compatible with that for a non-buckled hollow shell. Moreover, it is interesting to note that the compression resistance after buckling is approximately in proportion to the net shell-wall area, and independent of the thickness or the number of shell-walls. These investigations may quantitatively reveal a mechanism adopted by the nature: rolling the flat thin-layered composites into a filled concentric multi-walled cylindrical shell to achieve better compression resistance. The biological concentric shell can also be viewed as a double-leveled hierarchical structure, which is capable to sustain more complex loadings than the bottom leveled structure. 相似文献