The Solution for Axisymmetrical Shells with Abrupt Curvature Change(Corrugated Shells)by the Finite Element Method

It has been noted in the present paper that the finite element method using linear elements for solving axisymmetrical shells cannot be applied to the analysis of axisymmetrical shells with abrupt curvature change,owing to the fact that the influence of the curvature upon the angular displace-ments has been neglected.The present paper provides a finite element method using linear elements in which the influence of curvature is considered and the angular displacements are treated as continuous parameters.This method has been applied to the calculation of corrugated shells of the type C,and compared with the experimental results obtained by Turner-Ford as well as with the analytical solution given by Prof.Chien Wei-zang.The compari-sons have been proved that this theory is correct.     

由横向稀肋加固的斜锥壳的渐近解法

在文献[1]中作者得到了具有刚性加强端的斜锥壳的渐近解法.本文在此基础上进一步讨论横向稀肋加固的斜锥壳的渐近解法.所谓“稀肋”是指相邻两肋的简单边界效应相互影响在工程精度范围内可忽略不计的肋条,例如肋间距l≥3(rh)~(1/2)时(2h——薄壳厚度,r——两肋处壳体的最大平均半径).对于本文所讨论的常用的肋条横截面尺寸,分析结果表明,作为应力状态的第一次渐近解[误差为(h/λ)~(1/2)量级,λ——壳体中心面的特征曲率半径],肋对壳体薄膜应力状态没有影响.而在求解简单边界效应时,可将肋与壳的连接处看成弹性固支边界来处理,即认为此处的壳体转角γ_1为零,而周向应变ε_2等于肋的应变值。在分析过程中,讨论了肋截面形心偏心及形心主轴偏斜等因素对壳体应力状态的影响,证明了在第一次近似时它们可忽略不计. 为了验证所得结果的精确程度,在文献[1]的试件上,进一步作了具有稀肋加强的斜锥壳的电测试验.试验结果证实,本文所得的渐近解的误差基本上在(h/λ)~(1/2)及斜锥偏度m~2的量级范围内. 为了节省篇幅,本文不再给出斜锥壳各基本应力状态的内力及位移表达式,以及它们的待定函数的确定方法,需要时可参阅文献[1].     

聚氟硅氧烷处理的微纳表面水流减阻研究

本文成功制备了聚氟硅氧烷处理的微纳结构表面,并研究了其宏观水流减阻特性.首先,采用包覆工艺对粉煤灰球形微珠进行表面纳米化处理,制备出微纳结构复合微珠颗粒,并利用聚氟硅氧烷对复合微珠进行表面疏水处理;然后以硅橡胶为黏接剂将表面疏水化的复合微珠涂覆于槽道表面,制备出宏观尺度的超疏水性表面槽道.研究表明:聚氟硅氧烷处理的微纳结构粉煤灰复合微珠制备的宏观尺度超疏水性表面槽道与相同尺寸的普通表面槽道相比,当雷诺数Re＜ 1500时,层流减阻为22.6;,而Re＞ 1500时,湍流减阻达到76.5;.     

The solution for axisymmetrical shells with abrupt curvature change (corrugated shells) by the finite element method

It has been noted in the present paper that the finite element method using linear elements for solving axisymmetrical shells cannot be applied to the analysis of axisymmetrical shells with abrupt curvature change, owing to the fact that the influence of the curvature upon the angular displacements has been neglected. The present paper provides a finite element method using linear elements in which the influence of curvature is considered and the angular displacements are treated as continuous parameters. This method has been applied to the calculation of corrugated shells of the type C, and compared with the experimental results obtained by Turner-Ford as well as with the analytical solution given by Prof. Chien Wei-zang. The comparisons have been proved that this theory is correct.     

CuO—ZrO20—CeO2复合氧化物的催化性能研究

研究了氧化铜的加入对锆铈复合氧化物的结构与性能的影响,发现氧化铜的加入可降低氧化铈的还原温度,稳定复合氧化物的立方结构,提高对CO氧化的催化活性,增加铈含量能提高催化剂的活性,而硫酸盐等可使催化剂的活性降低,掺铜锆铈复合氧化物催化剂的活性几乎不受高温灼烧的影响,是一种具有较高热稳定性的催化剂。