上海世博会世博轴阳光谷钢结构施工关键技术

世博轴阳光谷是由矩形截面杆件构成的单层网壳结构,此种结构无论构件的制作还是安装难度都非常大,因此在施工过程中应用了多种特殊机械设备和施工技术。介绍了阳光谷施工过程中应用的关键技术。     

AE testing of a low-alloy steel pressure vessel

Testing pressure vessels in the field is generally conducted within a given range of test pressures, determined beforehand according to specified criteria. Thus monitoring of flaw growth using AE is carried under restricted conditions. To study the AE activity of flaws in welded seams of a pressure vessel (made of low-alloy steel) at different stages of growth and at different strains, tests were conducted on both spherical and cylindrical pressure vessels containing different artificial flaws. For given test conditions, the relationships between AE activity of artificial flaws and measured strains were studied. These tests form an important basis for the testing and assessment of engineering pressure vessels in the field.     

METHOD FOR CALCULATION AND SIMULATION ON PROPAGATION OF SURFACE CRACK ON SPHERICAL VESSELS MADE OF STEELS

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建筑结构球形支座设计分析

建筑结构中球形支座与公路桥梁中的球形支座受力形态存在显著差异,往往需要承受很大的水平荷载.针对球形支座在水平力作用下转动灵活性减弱的缺点,对传统球形支座形式提出了改进方法;对各种复杂应力状态下的球形支座进行了设计验算,所采用的实用设计方法可供结构设计人员参考;在同济大学国家重点实验室对球形支座进行了试验.     

不同矢跨比单层球面网壳的稳定性态

本文深入分析了工程中常用的六种单层球面网壳的稳定性态,对不同形式单层网壳在不同矢跨比和荷载形式的条件下进行了线性稳定及几何非线性稳定分析,说明单层球面网壳失稳的类型与矢跨比的关系,为工程应用提供有价值的数据资料。     

呼伦贝尔城市规划展览馆钢结构屋顶结构设计

呼伦贝尔城市规划展览馆屋顶造型为白云屋面,呈现出草原上一片云的建筑设计方案,结构形式采用双向正交桁架式网架。根据当地严寒气候条件以及屋顶独特造型,对结构各项荷载进行逐一分析,通过设置双向、单向球形铰支座释放内力,调节钢结构屋盖对下部混凝土结构的不利影响,利用SAP 2000有限元结构软件进行设计及计算,使结构经济合理,既能满足建筑造型要求,又能实现预定的性能目标。     

An artificial neural network model for the prediction of critical submergence for intake in a stratified fluid medium

Density differences may occur because of temperature differentials, suspended sediments, dissolved salts or other chemicals. Most of the large surface reservoirs are stably stratified throughout most, or all, of the year. One of the means of assisting the management is to allow a selective withdrawal from the reservoir. And while an intake is used for withdrawal (from the lower layer), a maximum discharge is required not allowing the uptake of the upper layer fluids. The value of the intake's vertical distance from the upper layer elevation (submergence) when the upper layer fluids begin to be drawn into the intake is known as ‘critical submergence’. In this study, the critical submergence for a circular intake pipe in a stratified body (which has different layer thickness) is investigated. Experiments were conducted on a vertically flowing downward intake pipe in a still-water reservoir. Artificial neural network (ANN) models and formulas, which are found by the theoretical analysis of critical spherical sink surface (CSSS), are used for the analysis of experimental results. The CSSS has the same centre and discharge as the intake. The ANN model and CSSS results are compared with the experimental results.     

肋环型球面空腹网壳结构的静力性能分析

空腹网壳是由平板型空腹网架演化而来的新型曲面空间网格结构,形式多样,为了解其中肋环型球面空腹网壳结构在竖向静载作用下的力学性能.本文采用空间梁单元,在边界上、下弦节点均约束线位移时共计算了22个算例,讨论了矢跨比、网壳厚度、网格圈数等参数对其变形和内力的影响.分析表明.肋环型球面空腹网壳可看作是两个具有相同曲率中心的单层网壳通过竖腹杆连接而共同工作,其矢跨比不官小于1/6,网壳厚度和网格圈数对结构力学性能的影响较小.本文还进行了这种结构与单层网壳的对比分析,表明其具有良好的技术经济指标.     

非线性扁球网壳的优化设计

分析了非线性变壁厚扁球壳的有矩内力,将其表达成辐角ψ的函数.运用塑性理论中的Tresea屈服条件,进行结构弹塑性阶段的内力研究.并用优化理论的满应力指数法分段进行壁厚的满应力优化设计.给出扁球网壳各杆件的最优尺寸.通过一个算例说明非线性扁球网壳优化设计的过程,并给出内力计算的表格和材料选用的表格.实现非线性扁球网壳的优化设计.     

非线性扁球网壳的优化设计探讨

在文献[1、2]基础上,分析了非线性变壁厚扁球壳的有矩内力,并将其表达成辐角φ的函数。然后,运用Tresea屈服条件,进行扁球壳壁厚的满应力优化设计。再将此球壳离散成网壳,实现非线性扁球网壳的优化设计。