对《锥壳的合理计算》一文的更正

天津市建筑科学研究所周厥耕同志来信对本刊1983年第3期发表的何崇璋同志《锥壳的合理计算》一文提出了宝贵意见,其中最主要是指出何文公式(22)是错误的,另外按何文计算,也有很大误差。并认为诺氏的一般旋转壳的有矩内力公式对锥壳是适用的。原文作者同意前一个意见,并从量纲和近似解的误差范围上作如下的更正和补充。     

板锥网壳结构的超级有限元分析

板锥网壳结构是一种新型的组合网壳。本文在对这类结构有限元法分析的基础上 ,根据板锥网壳结构的构成特点 ,应用超级元分析的基本思想 ,对这类结构进行了分析 ,给出了这类结构超级元分析基本公式。算例分析结果表明 :与一般有限元法相比 ,超级元法大大节省了计算量 ,结点自由度可降二个数量级 ,且分析结果和有限元法基本吻合 ,为这类大跨空间结构应用微机分析提供了一种新的方法     

板锥网索结构的超级有限元分析

板锥网索结构是一种新型的组合网壳。本文在对这类结构有限元法分析的基础上，根据板锥网壳结构的构成特点，应用超级元分析的基本思想，对这类结构进行了分析，给出了这类结构超级元分析基本公式。算例分析结果表明：与一般有限元法相比，超级元法大大节省了计算量，结点自由度可降二个数量级，具分析结果和有限元法基基吻合，为这 类大跨空间结构应用微机分析提供了一种新的方法。     

板锥网壳结构的抗风分析

板锥网壳结构是由薄板及钢管组合而成的一种轻质高强、技术经济效益良好的新型空间结构.本文应用谐波法模拟板锥网壳结构所受风荷载,并研究其风致响应特性.根据板锥网壳结构特点,基于CFD方法,采用数值风洞技术模拟结构周围风压变化,得到了板锥网壳结构的风荷载体型系数,并和荷载规范推荐的常规网壳结构的风荷载体型系数进行了比较.采用结构通用分析软件,通过模拟结构周围风压变化,对板锥网壳结构进行了风振响应时程分析,并对不同材料的板锥网壳结构风振响应分析结果进行了对比.为板锥网壳结构的抗风设计提供理论依据,得到了一些可应用于工程实际的重要结论.     

钢管塔塔柱与腹杆插板连接点的弹性受力分析

本文根据薄壁圆柱壳的有矩理论推导了塔柱在节点板造成的横向弯矩作用下的内力和变形公式 ,计算并比较了 4种截面的塔柱在轴力和附加横向弯矩共同作用下的内力 ,同时 ,讨论了该横向弯矩造成的局部应力对塔柱的影响 ,并比较了不同节点板尺寸和塔柱中最大复合应力的关系。     

板锥网壳结构的承载能力分析

板锥网壳结构是一种受力性能合理,技术经济效益良好的新型空间结构形式。本文考虑板片和杆件协同工作时的几何非线性,采用弧长法跟踪荷载—位移全过程平衡路径,对板锥网壳结构的极限承载力性能进行全过程非线性跟踪分析,确定其稳定性能及杆件和锥体单元板件屈服顺序,对板锥网壳结构的破坏机理和极限承载力等问题进行了研究,并与普通双层网壳结构进行了比较,得出了可应用于工程实践的重要结论。     

圆锥式焦炭破碎机

山西省建筑工程公司安装处加工连锻工组的同志们,自己设计,利用废旧零件,制成了焦炭破碎机。工作原理:电动机经皮带轮和伞齿轮二级减速后,驱动装配在主轴上的内锥筒旋转。主轴与内锥筒有10毫米的偏心矩,因而内锥筒在外锥筒中是作偏心迥转。由上部投料,利用内外锥筒上的牙条的相对运动,将     

板锥网壳结构的静力特性分析

板锥网壳结构是一种受力性能合理、技术经济效益良好的新型空间结构形式.作者对板锥网壳结构的连接构造进行了探讨,采用组合结构有限元法对板锥网壳结构的静力特性及其影响因素进行了系统分析研究,并与普通双层网壳结构进行了比较.分析结果表明,板锥网壳结构比双层网壳结构具有更大的优越性.     

对称锥台旋转壳体影响系数的简化计算方法

锥台旋转壳体具有对称的平面垂线与壳旋转轴,这种壳体往往会遇到更大的外壳组件,这些锥台可以拥有各种各样的几何形状,如球形、椭圆形、环形、抛物线或双曲线形。本文提出了一种新方法,简化了旋转壳体影响系数的推导过程。关键之处在于通过将边缘壳体分解为对称和反对称组件,减少了未知数的数量。     

板锥网壳结构的形态分析

板锥网壳结构是一种受力性能合理 ,技术经济效益良好的新型空间结构形式。本文提出板锥网壳结构的合理结构形式和分类 ,对其锥体单元进行形体分析 ,并对板锥网壳结构的选型原则进行了探讨     

Bending analysis of a truncated conical shell subjected to asymmetric load

Bending analysis of a truncated conical shell of revolution subjected to asymmetrical bending has been undertaken by using an approximate theory similar to the Donnell's theory for cylindrical shells. A method of solution suggested by Budiansky and Radkowski⁹ has been used in this study. Numerical results obtained from this solution have been compared with those obtained from the literature. The results of bending theory have also been compared with that of membrane theory and it is shown for the type of loading considered here that membrane theory is valid over a large portion of the shell.     

Free vibration analysis of joined conical shells: Analytical and experimental study

Natural frequencies and mode shapes of two joined isotropic conical shells are presented in this study. The joined conical shells can be considered as the general case for joined cylindrical–conical shells, joined cylinder–plates or cone–plates, conical and cylindrical shells with stepped thicknesses and also annular plates. Governing equations are obtained using thin-walled shallow shell theory of Donnell and Hamilton׳s principle. The continuity conditions at the joining section of the cones are appropriate expressions among stress resultants and deformations. The equations are solved assuming trigonometric response in circumferential and series solution in meridional directions and all combinations of boundary conditions can be assumed in this method. The results are compared and validated with the available results in other investigations and also modal testing. The effects of semi-vertex angles and meridional lengths on the natural frequency and circumferential wave number of joined shells are investigated.     

Bending and stretching actions in shallow domes. Part 1. Analytical derivations

In this two-part set of articles the response of shallow axisymmetric shells with circular plan is investigated with the aid of the two-surface shell theory. Such an approach has the unique advantage of elucidating, both qualitatively, and quantitatively, the complex—and key—interaction of bending and stretching actions in such shells in a simple and direct manner. Although discussion centres upon a shallow paraboloid of revolution, the general features emerging from the study are, obviously, relevant for the generic family of shallow domes (e.g. spherical) covering the various limiting cases of support around their circumference.This first paper begins with a two-surface exposition of the set of equations describing the behaviour of the shell. Next, analytical bending solutions to the specific practical problem wherein the shell is subjected to uniformly distributed vertical loading (corresponding, say, to its self-weight) are presented; and this is followed by the working out of closed-form expressions for the distributions of bending and stretching effects in theshell under consideration.     

网状球壳的连续化分析方法

本文对四向杆系、三向杆系、两向杆系组成的各种网状球壳,探讨了基于连续化计算模型的拟壳分析法,给出了网壳等代薄膜刚度和抗弯刚度的表达式,建立了轴对称网状球壳拟壳法的一般性基本方程式,并采用薄膜理论加边界效应的分析方法进行计算。文中给出了如何由壳体内力反算各种网状球壳杆件内力的计算公式,文末附有算例。计算表明,这种连续化的拟壳分析法比较方便,手算电算均可。此外,本文还就常用网状球壳的形式和分类作了讨沦。     

GBT formulation to analyse the buckling behaviour of isotropic conical shells

This paper presents a Generalised Beam Theory (GBT) formulation developed to analyse the elastic buckling behaviour of isotropic conical shells with constant thickness under axial compression. The GBT approach provides a general solution for 1st and 2nd order analysis using bar elements capable of describing the global and local deformations. The kinematic relations of the theory of thin shells are greatly simplified by the assumptions of null membrane shear strain and transverse extension before they are used for the evaluation of the strain energy variation. Because of the cross-section variation specific to conical shells, the mechanical and geometric properties are no longer constant along the bar axis as it is the case of cylinders and prismatic thin-walled structures. This formulation is validated by comparison between GBT results and values obtained by means of shell finite element analyses.     

Thermal buckling of FGM shells resting on a two-parameter elastic foundation

This paper focuses on the thermal buckling analysis of FGM shells resting on the two-parameter elastic foundation. Material properties of the constituents are graded in the thickness direction according to the power-law distribution. The surrounding elastic medium is modeled as an elastic foundation of the Pasternak-type. After giving the fundamental relations, the stability and compatibility equations of an FGM truncated conical shell subjected to thermal load and resting on a two-parameter elastic foundation have been derived. Critical temperature differences of FGM truncated conical shells with or without elastic foundations subjected to non-linearly distributed temperature across the thickness of the shells are obtained by solving eigenvalue problems. The appropriate formulas for FGM cylindrical shells with or without elastic foundations are found as a special case. In order to assure the accuracy of the present study, convergence properties of the critical temperature are examined in detail.     

Stress analysis of functionally graded open cylindrical shell reinforced by agglomerated carbon nanotubes

In this paper, stresses due to bending behavior of functionally graded carbon nanotube-reinforced (FGCNTR) open cylindrical shells subjected to mechanical loads is studied. The material properties of FGCNTR shells are assumed to be graded in the thickness direction, and are estimated using a two-parameter micromechanics model in which Eshelby–Mori–Tanaka approach is employed. The primary bending formulation is based on the linear, small-strain, three-dimensional elasticity theory. In addition, the cylindrical shells are analyzed using the third-order shear deformation theory (TSDT). In order to discretize the governing equations, the two-dimensional generalized differential quadrature method (2-D GDQM) in the thickness and longitudinal directions and the trigonometric functions in tangential direction are used. The effects of agglomeration parameters, CNTs volume fraction, and CNTs distribution through the thickness on the bending behavior of FGCNTR open cylindrical shells are studied. In addition, the mechanical stresses obtained from 3-D elasticity are compared with those obtained using TSDT for a different range of geometric and agglomeration parameters.     

常用旋转薄壳通用计算模式

本文是根据弹性薄壳理论,对部分应用非常广泛的旋转壳,通过它们内在的联系导出以超几何函数作为统一计算模式,使复杂的壳体分析(多种函数表达)规范化,便于掌握和运用.文中较多地涉及超几何方程在极限状态时的新方程解,故从应用角度称它们为“退化超几何方程”及“退化超几何函数”解.     

地基上混凝土梁的温度应力

地基上混凝土梁常需控制温度应力以避免裂缝。本文首先简要介绍马斯洛夫应力解,然后用弹性力学方法给出地基对梁的温度变形的抗力系数,从而得到地基上梁的温度应力的一套完整解法。根据地基弹性模量及梁的长高比,对梁所受到的地基约束作用分为4类:(a)弯曲变形完全约束,水平变形部分约束;(b)弯曲变形完全约束,水平变形无约束;(c)弯曲变形部分约束,水平变形无约束;(d)水平变形和弯曲变形均无约束。对于每类约束情况分别给出了简洁的温度应力计算公式,使计算得到简化。给出了混凝土弹性模量和温度随龄期而变化时的计算方法。指出了目前工程界采用的地基上梁温度应力计算方法的不足之处。     

Investigation of pointed domes—I. Theory

A theoretical method of shell analysis has been utilized and, with the help of certain innovations, the study of pointed domes subjected to pointed loading is presented in this paper.To derive an analytical expression for the pointed dome, the general theory of shell of revolution is used to take into account the effect of membrane and bending stress field. Additionally the general classical approach of analytical multi-shell analysis is utilized to obtain the solution.This solution is applied to a pointed dome with a given dimension and the membrane stress field was calculated. The results thus obtained give a good approximation of the internal force field in the central portion of the dome. However this is not true near the lower boundary and near the kinked vertex of the dome.The values of internal meridional bending moment and meridional shear have also been calculated. These indicate that the bending field diminishes in magnitude as we move away from the kinked region.