Hot Expansion of a Thin-Walled Cylindrical Shell of Porous Material

A system of equations describing the hot expansion of a thin-walled cylindrical shell of porous material by internal pressure was obtained. The solution was based on one of the simplest creep theories, namely, work hardening theory. The radial, meridial, and volume rates of creep deformation were calculated in comparison with the basic circumferential deformation rate of the shell. The numerical results were obtained by considering a process of stepwise loading of the shell. It was established that porosity in the material decreases the limiting value of internal pressure of the shell.     

内压圆柱壳内伸式接管补强结构应力分布

针对内压圆柱形容器大开孔率内伸式接管补强结构,进行了三维线弹性有限元应力分析,得到内压圆柱壳内伸式接管补强结构的应力分布规律。以DXF格式文件为中介,用数学方法自动生成的有限元计算模型是可靠的,应用这个模型进行有限元分析可以得到内压圆柱壳内伸式接管补强结构的应力集中系数,为研究其应力集中系数规律奠定了基础。     

Buckling analysis of multi-walled carbon nanotubes under combined loading considering the effect of small length scale

The torsional and axially compressed buckling of an individual embedded multi-walled carbon nanotube (MWNTs) subjected to an internal and/or external radial pressure was investigated in this study. The emphasis is placed on new physical phenomena which are due to both the small length scale and the surrounding elastic medium. Multiwall carbon nanotubes which are considered in this study are classified into three categories based on the radius to thickness ratio, namely, thin, thick, and almost solid. Explicit formulas are derived for the van der Waals (vdW) interaction between any two layers of an MWNT based on the continuum cylindrical shell model. In most of the previous studies, the vdW interaction between two adjacent layers was considered only and the vdW interaction among other layers was neglected. Moreover, in these works, the vdW interaction coefficient was treated as a constant that was independent of the radii of the tubes. However, in the present model the vdW interaction coefficients are considered to be dependent on the change of interlayer spacing and the radii of the tubes. The effect of the small length scale is also considered in the present formulation. The results show that there is a unique buckling mode (m,n) corresponding to the critical shear stress. This result is obviously different from what is expected for the pure axially compressed buckling of an individual multi-walled carbon nanotube.     

一种新板壳单元在拱坝应力分析中的应用

提出一种新的板壳单元,建立以结点位移为未知量的平衡方程组,组装得到的整体刚度矩阵为稀疏带状矩阵。与常规试载法相比,所需存储容量小,计算速度快。该方法已在实际工程中得到了应用,并取得令人满意的结果。     

Geometrically non‐linear thermoelastic analysis of functionally graded shells using finite element method

A finite element formulation governing the geometrically non‐linear thermoelastic behaviour of plates and shells made of functionally graded materials is derived in this paper using the updated Lagrangian approach. Derivation of the formulation is based on rewriting the Green–Lagrange strain as well as the 2nd Piola–Kirchhoff stress as two second‐order functions in terms of a through‐the‐thickness parameter. Material properties are assumed to vary through the thickness according to the commonly used power law distribution of the volume fraction of the constituents. Within a non‐linear finite element analysis framework, the main focus of the paper is the proposal of a formulation to account for non‐linear stress distribution in FG plates and shells, particularly, near the inner and outer surfaces for small and large values of the grading index parameter. The non‐linear heat transfer equation is also solved for thermal distribution through the thickness by the Rayleigh–Ritz method. Advantages of the proposed approach are assessed and comparisons with available solutions are presented. Copyright © 2007 John Wiley & Sons, Ltd.     

利用三辊滚板机卷制圆锥台筒节的原理和方法

压力容器制作中,经常遇到圆锥台筒节(大小头)制作,通过技术革新解决生产中的疑难问题,可减轻劳动强度,提高劳动效率,提高制作产品质量。     

圆柱壳的半无矩理论分析

运用半无矩理论，对带有边梁的圆柱壳屋盖使用三角级数求解，并通过算例，将计算结果分别与丹尼尔(Donnell)的弯曲理论和肖勒(Schorer)的简化理论进行比较，证明该方法有效。     

《中低压双壳程换热器系列工程图》的开发

将高压双壳程换热器强化传热的技术移植到中低压换热器上,并开发编制了《中低压双壳程换 热器系列工程图》。用于哈尔滨石化分公司的加氢精制-临氢降凝等装置中,收到了良好的效果。