复杂造型高层建筑幕墙安装技术

望京SOHO-T3工程幕墙总面积达6.77万m~2,包括玻璃幕墙、铝板幕墙、铝合金百叶等。施工中针对幕墙外形变化多、单体重量大等特点,通过采取布设坐标控制网、严格控制预埋件定位、龙骨精确加工等措施,保证了多种幕墙顺利安装到位。     

钢带增强聚乙烯螺旋波纹管和检查井连接新方式

钢带增强聚乙烯螺旋波纹管,是一种把钢和聚乙烯的优势整合为一体的钢塑复合管。目前,所有钢骨架管和检查井的连接都是钢骨架管和混凝土或砖砌检查井直接连接。该文介绍了钢骨架管和实壁检查井连接的新方式,通过这种改进的连接方式,克服了钢骨架管与实壁检查井的连接渗漏问题,实现了整条管道系统100%无渗漏。     

振动时效工艺在消除膨胀波纹管残余应力中的应用

膨胀波纹管体冷压成型后存在较大的残余应力常导致管端面严重变形和尺寸不稳定,已成为制约管体焊接连接质量和效率提高技术瓶颈。探索振动时效法用于消除或减弱波纹管体残余应力的可行性。结合室内试验和现场试验数据,建立振动时效法适用的关键技术、工艺参数、评价方法以及后处理分析手段。采用所建立的评价体系,通过振动时效参数曲线观测和盲孔法残余应力测量,评定了该试验振动过程及振动时效效果有效性,这证明振动时效工艺可显著降低膨胀波纹管残余应力,能够满足膨胀波纹管焊接等工程需要,提高其尺寸稳定性。     

有限元分析在波纹管补偿器中的应用

简述了金属波纹管的发展现状,介绍了有限元分析在金属波纹管设计中的应用方法、价值和前景。     

波纹管阀门的密封结构及其影响因素

文中根据波纹管阀门的使用环境和功能要求,确定了阀门的主要结构材料,设计了阀门的内、外密封结构。在阀门的内密封结构上,采用形如刀口的平面密封,具有平面密封的特点,同时密封轴向力适中;在阀门的外密封结构上,采用与外界无漏点的波纹管密封。同时,内密封性能是波纹管阀门的一个重要技术指标,在研究波纹管阀门内密封的密封机理基础上,分析了波纹管阀门内密封性能的影响因素,如介质的物理性质、密封副质量、表面粗糙度、密封宽度、密封比压等,可为波纹管阀门的设计提供理论依据。     

波纹管换热器管板的设计计算与强度校核

利用有限元方法进行波纹管分析讨论波纹管换热器管板计算,给出了波纹管换热器管板强度计算方法,即将波纹管换热管进行等刚度折算为同直径(外径)的光管,通过对折算前后两种计算结果的对比分析发现,本文采用的计算方法,不仅更为全面,且更便于实际操作和工程应用。     

Turbulent heat transfer enhancement in a heat exchanger using helically corrugated tube

The augmentation of convective heat transfer in a single-phase turbulent flow by using helically corrugated tubes has been experimentally investigated. Effects of pitch-to-diameter ratio (P/D_H = 0.18, 0.22 and 0.27) and rib-height to diameter ratio (e/D_H = 0.02, 0.04 and 0.06) of helically corrugated tubes on the heat transfer enhancement, isothermal friction and thermal performance factor in a concentric tube heat exchanger are examined. The experiments were conducted over a wide range of turbulent fluid flow of Reynolds number from 5500 to 60,000 by employing water as the test fluid. Experimental results show that the heat transfer and thermal performance of the corrugated tube are considerably increased compared to those of the smooth tube. The mean increase in heat transfer rate is between 123% and 232% at the test range, depending on the rib height/pitch ratios and Reynolds number while the maximum thermal performance is found to be about 2.3 for using the corrugated tube with P/D_H = 0.27 and e/D_H = 0.06 at low Reynolds number. Also, the pressure loss result reveals that the average friction factor of the corrugated tube is in a range between 1.46 and 1.93 times over the smooth tube. In addition, correlations of the Nusselt number, friction factor and thermal performance factor in terms of pitch ratio (P/D_H), rib-height ratio (e/D_H), Reynolds number (Re), and Prandtl number (Pr) for the corrugated tube are determined, based on the curve fitting of the experimental data.     

A Proposed Tool to Determine Dynamic Load Distribution between Corrugated Boxes

This paper summarizes the dynamic analysis of the interaction of corrugated boxes in transport using a pressure‐mapping system. The dynamic contact forces on the contact area between boxes in both vertical and horizontal directions were measured, and the position of the instantaneous centre of force was traced, from which the pitch motion of boxes relative to each other was studied. The level‐crossing diagrams of the contact forces show a Rayleigh distribution for the vertical contact and a Gaussian distribution for the horizontal contacts. The contact force and acceleration power spectral density from accelerometers and pressure‐mapping system were compared. The results show that a pressure‐mapping system is an interesting tool for the analysis of the dynamic performance of systems of corrugated boxes under different stacking and loading conditions. Copyright © 2011 John Wiley & Sons, Ltd.     

多工作面施工方案在某波形钢腹板箱梁桥中的应用

结合实际工程,通过对多工作面施工方案与普通施工方案相比较,总结出了多工作面施工方案的诸多优点。具体从挂篮的结构形式、安装移动施工流程,以及数值分析探讨了波形钢腹板箱梁桥的多工作面施工方案,并进一步验证了多工作面施工方案结构的安全性。由于这种多工作面施工方案可以减轻挂篮自重、大幅度缩短工期等,因此可降低总体造价,达到一定的经济效果。     

Shear strength of trapezoidal corrugated steel webs

Corrugated webs are used to increase the shear stability of the steel webs of beams and girders and to eliminate the need for transverse stiffeners. This paper focuses on the shear strength of corrugated steel webs with trapezoidal corrugations. Previously developed formulas for predicting the shear strength of steel trapezoidal corrugated webs, along with the corresponding theory, are summarized. A new formula is developed, which considers interaction among the various shear failure modes. More than 100 test results from previous research are organized and evaluated according to relevant test specimen parameters. The conditions of many of these tests are found to be inconsistent with the theoretical conditions assumed in deriving the shear strength formulas. The various formulas for predicting shear strength are then compared with selected test results. The new formula is shown to be more accurate than previous formulas for estimating the shear strength of corrugated steel webs.