共查询到19条相似文献,搜索用时 203 毫秒
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静水压力下具有轴对称初始缺陷圆柱壳承载能力研究 总被引:1,自引:0,他引:1
文章针对含有轴对称初始缺陷和局部轴对称凹陷的圆柱壳在静水压力下的稳定承载能力问题进行了研究。通过一种数值计算方法,给出了初始缺陷幅值、壳体半径与厚度比、壳体长度、局部凹陷长度及位置对静水压力下圆柱壳屈曲临界压力的影响。并针对不同缺陷幅值对圆柱壳的刚度进行折减,给出了初始缺陷幅值与刚度折减系数的关系。研究结果表明,对于轴对称初始缺陷对圆柱壳稳定承载能力的影响,本质上是降低圆柱壳轴向弯曲刚度和轴向的薄膜刚度从而造成圆柱壳稳定承载能力的下降,因此针对轴对称初始缺陷可以增加纵筋提高其弯曲刚度,增加稳定承载能力。 相似文献
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由于初始缺陷会引起轴压圆柱壳失稳载荷很大程度的折减,本文基于刚度折减方法,推导建立轴压圆柱壳失稳载荷计算公式,分析轴对称缺陷对轴压圆柱壳各部分刚度的影响。结果表明,轴对称初始缺陷对轴压圆柱壳薄膜刚度影响较大,初始缺陷经过了圆柱壳失稳波数的二次方放大。 相似文献
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在推导环肋圆柱壳屈曲临界载荷的基础上,通过能量与结构刚度之间的关系,分析了肋骨弯曲刚度、扭转刚度和压缩刚度对环肋圆柱壳失稳载荷的影响。分别折减肋骨弯曲刚度和壳板刚度,研究了不同位置的肋骨在环肋圆柱壳总体稳定性中的作用,并将单根肋骨刚度折减系数转换成所有肋骨的平均折减系数;分析了壳板刚度对环肋圆柱壳总体稳定性的影响,给出了肋骨和壳板刚度同时折减时环肋圆柱壳总体稳定性的计算方法。为环肋圆柱壳的设计以及含缺陷圆柱壳承载能力的研究提供了一种理论参考。 相似文献
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圆柱壳是民用和军用海洋结构的主要构件。它在脉冲载荷作用下可能发生动力屈曲响应。本文提出了脉冲持续时间对圆柱壳动力屈曲效应的非线性有限元数值比较研究,同时也研究了脉冲与静水压力联合作用对浸潜圆柱壳屈曲的影响。在有限元模糊型中动力屈曲性能是建立在监视初始形状缺陷的非线性增长基础上的。 相似文献
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本文应用三种壳体理论,对静水压力作用下正交各向异性圆柱壳的弹性稳定性进行了比较分析.利用正交各向异性圆柱壳的内力表达式和在静水压力作用下的正交各向异性圆柱壳的平衡方程,推导出三个位移的微分表达式,并给出了三种理论的差异.针对两端薄膜简支边界条件,对壳体的稳定性进行了分析.讨论了正交各向异性对偏差的影响以及产生偏差的原因,并指出了文献[5]的一个错误. 相似文献
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圆柱形管状结构在海洋工程领域中应用较多,在进行结构设计时,需重点关注其侧向受载时的屈曲强度问题。通过理论分析和数值模拟,对比研究径向线性载荷变化下圆柱壳的屈曲行为,以经典的Donnell壳体理论为基础,得到圆柱壳的屈曲控制方程,并通过本征值分析方法得到结构屈曲的临界条件。采用有限元软件ABAQUS对线性变化径压下圆柱壳的屈曲进行数值仿真。分析得出径厚比是径向线性分布载荷下圆柱壳屈曲临界载荷的主要影响因素,三角形径压下屈曲临界载荷值约为均布径压下屈曲临界载荷值的2倍。 相似文献
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《Marine Structures》2003,16(5):397-415
This paper is the second part of the structure study of double cylindrical shell subjected to hydrostatic external pressure. The author makes researches on the relationship between inner and outer shells of pressurized double cylinders using equilibrium conditions of forces and deformation compatibility conditions with ring plate orthogonally connected to inner and outer shells and puts forward the expressions of longitudinal and circumferential forces of double pressurized cylinder. In this paper, equilibrium equations are established for a double cylindrical shell stiffened longitudinally and transversely and subjected to uniform hydrostatic external pressure by using an adjacent equilibrium method and a solution with high accuracy is presented to calculate theoretically critical pressures of panel buckling and interframe shell buckling. The solution can be used to both the double and single cylindrical shells without longitudinal stiffeners and therefore, it may be applied widely with higher accuracy. Also, some simplified formulae for the engineering application are given to calculate the panel buckling and the interframe shell buckling strengh. 相似文献
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The effect of hydrostatic pressure on the vibration dispersion characteristics of fluid-shell coupled structures was studied.Both fluid-loaded cylindrical shells and fluid-filled cylindrical shells were considered.Numerical analysis was applied to solve the dispersion equations for shells filled with or loaded with fluid at various hydrostatic pressures.The results for external pressure showed that non-dimensional axial wave numbers are nearly independent when the pressure is below the critical level.The in... 相似文献
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锥-环-柱结合壳的应力和稳定性 总被引:2,自引:0,他引:2
本文用解析法计算了受中面均布法向载荷作用的锥-环-柱结合壳中的应力值,并根据Trefftz准则计算了其失稳临界压力。计算结果说明,在总体几何尺寸与壳厚相同的情况下,锥-环-柱结合壳与锥-柱结合亮相比,过渡区的局部应力值显著减小,失稳临界压力提高。 相似文献
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从Fluegge关于圆柱壳的失稳方程出发,推导了正交各向异性圆柱壳在静水压力作用下,受到单位冲量作用的运动方程。本文使用模态叠加法求解瞬态响应方程,讨论了壳体参数和材料参数对于响应的影响,给出了部分结果。 相似文献
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Underwater cylindrical shell structures have been found a wide of application in many engineering fields, such as the element of marine, oil platforms, etc. The coupled vibration analysis is a hot issue for these underwater structures. The vibration characteristics of underwater structures are influenced not only by hydrodynamic pressure but also by hydrostatic pressure corresponding to different water depths. In this study, an acoustic finite element method was used to evaluate the underwater structures. Taken the hydrostatic pressure into account in terms of initial stress stiffness, an acoustical fluid-structure coupled analysis of underwater cylindrical shells has been made to study the effect of hydrodynamic pressures on natural frequency and sound radiation. By comparing with the frequencies obtained by the acoustic finite element method and by the added mass method based on the Bessel function, the validity of present analysis was checked. Finally, test samples of the sound radiation of stiffened cylindrical shells were acquired by a harmonic acoustic analysis. The results showed that hydrostatic pressure plays an important role in determining a large submerged body motion, and the characteristics of sound radiation change with water depth. Furthermore, the analysis methods and the results are of significant reference value for studies of other complicated submarine structures. 相似文献
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左成魁 《交通部上海船舶运输科学研究所学报》2014,(2):18-21
求解带肋圆柱壳屈曲压力的方法有很多,至今为止大部分人都把目光集中到了以电能量法来求解,因为用其它方法计算加强圆柱壳的屈曲压力是非常困难的.解决大圆柱壳大分舱结构的一个关键问题是求解带框架肋骨的环肋圆柱壳的总体屈曲.为此,提出一种计算带框架肋骨的环肋大圆柱壳总体弹性屈曲能量的方法. 相似文献