Thermoconductivity and thermoelasticity of thin isotropic shells heated by a moving heat pulse

The paper presents a solution to the problem of thermal conduction and thermoelasticity for a thin shallow spherical shell heated by a concentrated or local impulsive heat source moving over the shell surface. It is assumed that temperature is linearly distributed across the shell thickness and that the shell, on its sides, exchanges heat with the environment in accordance with Newton’s law of cooling. The Fourier and Laplace transforms are used to find an analytic solution. The dependence of the temperature field and stress/strain components on the type of heating and the form of heat source is studied __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 11, pp. 85–92, November 2006.     

Analysis of energy release rate for composite delaminated cylindrical shells subjected to axial compression

In this paper, the postbuckling governing equations and the analytical expression of the energy release rates associated with delamination growth in a compression-loaded cylindrical shell are derived by using the variational principle of moving boundary and the Griffith fracture criterion. The finite difference method is used to generate the postbuckling solutions of the delaminated cylindrical shells, and with these solutions, the values of the energy release rates are determined. In simulational examples, the effects of a wide range of parameters, such as delamination sizes and depths, boundary conditions, geometrical parameters, material properties and laminate stacking sequences on the energy release rates of axisymmetrical laminated cylindrical shells are intensively discussed.The English text was polished by Yunming Chen.     

Buckling and post-buckling of long pressurized elastic thin-walled tubes under in-plane bending

The present paper focuses on the structural stability of long uniformly pressurized thin elastic tubular shells subjected to in-plane bending. Using a special-purpose non-linear finite element technique, bifurcation on the pre-buckling ovalization equilibrium path is detected, and the post-buckling path is traced. Furthermore, the influence of pressure (internal and/or external) as well as the effects of radius-to-thickness ratio, initial curvature and initial ovality on the bifurcation moment, curvature and the corresponding wavelength, are examined. The local character of buckling in the circumferential direction is also demonstrated, especially for thin-walled tubes. This observation motivates the development of a simplified analytical formulation for tube bifurcation, which considers the presence of pressure, initial curvature and ovality, and results in closed-form expressions of very good accuracy, for tubes with relatively small initial curvature. Finally, aspects of tube bifurcation are illustrated using a simple mechanical model, which considers the ovalized pre-buckling state and the effects of pressure.     

含压电层的功能梯度柱壳的自由振动分析

基于三维弹性理论，导出了带有压电层的圆柱形梯度壳的动力学方程以及相应的边界条件，用幂级数展开法得到了求解该圆柱形梯度壳自由振动的三维精确公式．通过实例模型求解了该壳体的自由振动的固有频率；分析了不同电学边界条件对壳体的振动频率的影响。结果可评估各种近似理论解和数值解的正确性。     

复杂载荷作用下圆柱壳的弹塑性动力屈曲研究

对复杂载荷作用下圆柱壳的弹塑性动力屈曲问题进行了研究。基于Hamilton变分原理导出圆柱壳的运动方程 ,本构关系采用增量理论 ,借助增量数值算法求解动力方程组。结果表明 ,均匀径向外压对圆柱壳的轴向冲击的过程或冲击性态有较大的影响 ,并讨论了径向压力与轴向冲击载荷的幅值对结构临界动力屈曲载荷和临界动力失效载荷的影响。     

板锥网壳结构几何非线性受力性能的广义协调元分析

板锥网壳网络是一种新型的空间结构，它是在板锥单元和常规的双层刚壳结构的基础上组合形成的一种新型结构形式，具有良好的技术经济效益和建筑视觉效果。本文在对这类结构有限法分析的基础上，根据板锥网壳结构的构成特点，应用广义协调元的基本思想，对这类结构进行了分析，给出了这类结构广义协调元分析的基本公式。分析表明：广义协调元法适宜于板锥网壳结构的受力性能分析，广义协调元固有的简便，高效和可靠的特性，将会使结构分析得到更为可信和可靠的论证。     

薄壁柱壳的圆度及三维变形测量技术

本文采用一种新的形状位置（Ｐｒｏｆｉｌｉｍｅｔｒｙ）自动测量计算机处理方法,对钢质圆柱壳的椭圆度进行了测试。具体使用投影光栅,于壳体表现形成栅线影象,自动形成栅线光频率线性编码,用ＣＣＤ摄象机采集到频率编码壳体光栅影象,构成形西半球工波图。将载波的图象经过计算机图象系统获得数值图象。计算机经过快速富立叶变换法解码,输出频率位相值,经数据处理可得到精确的壳面尺度。     

剪切载荷下肋板的屈曲分析与优化

利用ANSYS有限元方法分析了一系列的肋板，研究了加强肋的作用，提出了 优化肋设计的限制条件. 结果表明，由横向肋板产生的栅格数目不能小于肋板的长宽比. 换 句话说，横向加强肋必须把平板的长度划分为小于等于宽度的段. 结果还显示，加强肋的优 化几何特性与板的屈曲从整体模态到局部模态转变点相应. 而且，所有具有相似长宽比和肋 数的肋板，具有一个特定的比值$EI_{s}/aD$, 此时抗剪应力最佳.     

On numerical solution of dynamic problems in the theory of reinforced shells

Dynamic problems for cylindrical shells reinforced with discrete ribs are examined. A numerical algorithm based on Richardson extrapolation is developed. Specific problems are solved, and the results are analyzed __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 5, pp. 50–56, May 2006.     

波纹钢屋盖结构板件相关屈曲的试验研究与分析

拱型波纹钢屋盖结构的受力机理异常复杂，波纹、加工制作过程中产生的变形和残余应力等初始缺陷在理论分析中很难精确定量描述。论文对波纹钢屋盖结构梯形截面板组进行了轴心和偏心压力作用下稳定承载能力的试验研究，并与理论结果进行了比较分析，试验与理论结果吻合较好。试验结果表明波纹板组具有较高的局部屈曲承载能力，但几乎无屈曲后承栽能力，与平板板组屈曲特性相比有显著差异。