不同脉动风相干函数对高层建筑风振响应的影响

首先介绍了3种较为常见的脉动风相干函数表达形式,然后基于随机振动理论在频域内推导了高层结构风振响应的无量纲化解析式,在此基础上对采用不同脉动风相干函数所得到的高层结构风振响应分析结果进行了比较.结果表明,不同脉动风相干函数对结构风振响应分析结果的影响主要体现在共振响应部分,采用不考虑频率项的相干函数所得到的风振响应分析结果要偏大60%左右.最后,对中国荷载规范给出的脉动影响系数ν计算提出了应乘以0.6～0.7折减系数的建议.     

Numerical simulation of flows around long-span flat roof

Long-span roof with span larger than height always has a complicated three-dimensional curve. Wind pressure on the roof is often influenced not only by the atmospheric turbulence, but also by the “signature” turbulence provoked in the wind by the structure itself. So it is necessary to study characteristics of flows around the roof. In this paper, three-dimensional numerical simulation of wind-induced pressure has been periormed on a long-span flat roof by means of Computational Fluid Dynamics （CFD） software ——FLUENT. The flow characteristics are studied by considering some parameters, such as wind direction, span-height ratio, roof pitch, flow characteristics, roughness of terrain. The simulation is based upon the Reynolds-averaged equations, in which Reynolds stress equation model （RSM） and SIMPLE technology, （Semi-Implieit Method for Pressure-Linked Equations） have been used. Compared with wind tunnel tests, the computational results have good agreement with the experimental data. It is proved that the results are creditable and the method is feasible.     

张拉式膜结构抗风设计

抗风设计一直是膜结构设计中的核心问题和难点问题。以Davenport提出的阵风荷载因子法为基础,结合张拉式膜结构的风振响应特点,提出一系列改进措施,初步建立了一种适用于张拉式膜结构抗风设计的实用化方法。采用随机模拟时程分析方法对几种典型形状的张拉式膜结构进行了较为系统的风致动力响应参数分析,总结了结构风振响应的规律。并在此基础上,依据提出的抗风设计方法给出了可供设计人员参考的风振系数取值。     

单层柱面网壳结构风振响应分析

风荷载在大跨度屋盖结构设计中常常起主要甚至决定性作用,这使得该类结构的风荷载及风致动力响应研究日益受到关注与重视。利用随机模拟时程分析方法对三向网格单层柱面网壳结构的风振性能进行了系统的参数分析,探讨了几何参数、气动参数、结构参数等因素对结构风振响应规律的影响,并在此基础上给出了可供单层柱面网壳结构抗风设计参考的风振系数。     

光伏玻璃企业现阶段发展现状

以H公司为例,运用战略管理等理论,通过调查资料等方法获取数据,在外部环境方面,采用PEST分析方法对公司的宏观环境进行总体分析,运用波特五力模型对超白压延玻璃行业进行分析,对公司外部环境进行综合评价,得出公司机遇大于威胁的结论;在内部环境方面,通过对公司优势和劣势进行分析,得出公司内部处于优势地位的结论;最后结合内外部因素的综合评价,运用SWOT模型提出公司的战略发展应选择增长型战略,并为公司制定支持新战略的策略方案。     

低温球磨制备纳米晶铝/铝基复合材料的研究进展和应用前景

详细介绍了国内外采用低温球磨粉末冶金法制备纳米晶铝及其铝基复合材料的研究进展。通过对比分析国内外在材料研制和工装设备研发等方面存在的主要差距,提出了国内在纳米晶铝应用研究中存在的问题、解决措施及发展方向。最后,对纳米晶铝/铝基复合材料未来的应用前景进行了展望。     

拉挤型CFRP管轴压性能

航天器骨架结构通常由轻质高强CFRP(carbon fiber reinforced polymer)复合材料管制成,其稳定承载力成为结构安全性能的一项重要指标。对CFRP短管进行轴压试验,重点研究碳纤维增强复合材料的刚度、极限强度以及细观破坏模式。基于Hashin破坏准则进行二次开发,采用ANSYS有限元软件对试验过程进行了数值模拟,数值结果表明,Hashin破坏准则可以较好地预测CFRP复合材料破坏时的极限承载力。基于Hashin破坏准则,采用弧长法对试验工况中的5组长细比的CFRP细长管进行数值模拟,绘制荷载-跨中挠度曲线,总结其破坏特点、变形特征,与试验对比吻合较好。通过参数分析,并根据试验结果与数值分析结果,拟合得到了拉挤型CFRP细长管稳定系数Φ与长细比λ之间的关系曲线,方便工程使用。     

Wind-induced vibration of single-layer reticulated shell structures

Aiming at the dynamic response of reticulated shell structures under wind load, systematic parameter analyses on wind-induced responses of Kiewitt6-6 type single-layer spherical reticulated shell structures and three-way grid single-layer cylindrical reticulated shell structures were performed with the random simulation method in time domain, including geometric parameters, structural parameters and aerodynamic parameters. Moreover, a wind-induced vibration coefficient was obtained, which can be a reference to the wind-resistance design of reticulated shell structures. The results indicate that the geometric parameters are the most important factor influencing wind-induced responses of the reticulated shell structures; the wind-induced vibration coefficient is 3.0 - 3.2 for the spherical reticulated shell structures and that is 2.8 - 3.0 for the cylindrical reticulated shell structures, which shows that the wind-induced vibration coefficients of these two kinds of space frames are well-proportioned.     

大跨度屋盖结构等效静风荷载分析方法及应用

将大跨度屋盖结构等效静风荷载分为平均分量、背景分量和共振分量3个部分.以荷载响应相关系数法为基础,结合本征正交分解法,用脉动风荷载的本征模态表示等效静风荷载的背景分量,用主导振型的惯性力表示等效静风荷载的共振分量.进一步提出2个重要指标,选择最主要的本征模态和结构振型表示等效静风荷载,建立荷载模态、结构振型和等效静风荷载之间的联系.将该方法用于一单层球面网壳,计算结果验证了该方法的可靠性.     

Dynamic performance of cable net facade with consideration of glass panels under earthquake

Shaking table tests and theoretical analysis were conducted to study the dynamic performance of cable net facade with consideration of glass panels under earthquake. Firstly,the dynamic response of cable net faade under earthquake was investigated with shaking table test. Then the working mechanism of glass panels in coordination with cable net was proposed. Accordingly,a numerical simulation model of glass panel's working in coordination with cable net was built for the dynamic analysis.And then the seismic response was analyzed with this model theoretically. The study indicates that the seismic response of the cable net with glass panels on most occasions is mainly decided by the symmetric modes,and the first vibration mode is dominant. The damping of cable net facade is mainly decided by glass panels. And it is very good for cable net faade to restrain its dynamic response under earthquake.