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The temperature field variation law and distribution characteristics of an orthotropic flat steel box girder under sunny conditions were analyzed through a field temperature test on the steel box girder of the operational Runyang Yangtze River Bridge(the suspension bridge part).Function optimization fitting and error analysis of the test data were conducted.A temperature gradient distribution curve applicable to a hexagonal flat steel box girder was proposed.Based on the measurement results,the temperature effect of an orthotropic flat steel box girder was analyzed using finite element method and the effects of different temperature gradient modes on the mechanical characteristics and stress distribution of the steel box girder were compared.Under sunny conditions,heat conduction in the flat steel box girder structure shows distinct "box-room effect" characteristics,and the actual temperature gradient distribution is inconsistent with the one suggested by the existing standards.The thermal stress of a steel box girder calculated from the measured temperature gradient mode exceeds that calculated from the standard,and the intensity approximates that under the action of designed vehicle loads.The temperature-induced stress is distributed centrally near the manufacturing welds of the orthotropic steel box girder,which should be considered in design,construction and research.Results from this study could supplement the existing bridge and culvert design standards. 相似文献
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Hu RenXiang Shan Xu Yuan GuangYuan Wang ShuWen Zhang WeiHang Qi Wei Cao Zhe Li YiRen Chen ManMing Yang XiaoPing Wang Bo Shao SiPei Li Feng Zhong XiaoQing Fan Dan Hao XinJun Feng ChangQing Su ZhenPeng Shen ChengLong Li Xin Dai GuYue Qiu BingLin Pan ZongHao Liu Kai Xu ChunKai Liu ShuBin An Qi Zhang TieLong Wang YuMing 《中国科学:技术科学(英文版)》2019,62(6):1015-1027
A low-energy ion spectrometer(LEIS) for use aboard three-axis stabilized spacecraft has been developed to measure ion energy per charge distribution in three-dimensional space with good energy-, angular-and temporal-resolutions. For the standard top-hat electrostatic analyzer used widely in space plasma detection, three-axis stabilized spacecraft makes it difficult to obtain complete coverage of all possible ion arrival directions. We have designed angular scanning deflectors supplementing to a cylindrically symmetric top-hat electrostatic analyzer to provide a half-space field of view as 360°×90°(–45°–+45°), and fabricated the LEIS flight model for detecting magnetospheric ions in geosynchronous orbit. The performance of this payload has been evaluated in detail by a series of simulation and environmental tests, and the payload has also been calibrated through laboratory experiments using a low-energy ion source. The results show that capabilities of the LEIS payload are in accordance with the requirements of a magnetospheric mission. 相似文献
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伯明翰中心繁荣的开发区为Doka公司新近开发的导航攀升系统(GCS),Framax脱 模角落和平台提升系统提供了绝佳的表演场。Orion大楼坐落在航运大街,靠近新街火车站和斗牛场购物中心,它包括300间公寓住宅,一个三层的玻璃顶楼, 相似文献
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Runyang Bridge is a newly built cable-supported bridge that crosses the Yangtze River in China. The bridge is composed of
one suspension bridge and one cable-stayed bridge. During the construction of the bridge, a structural health monitoring system
(SHMS) was installed, which was designed by the Southeast University. Since the bridge was open to traffic, quantities of
structural ambient responses have been recorded by the SHMS. And, it’s really important to extract structrural information
from these records for health monitoring. This paper presents the study on modal identification of the bridge. The dynamic
properites including modal frequencies, mode shapes and damping ratios are extracted from the ambient responses. Two identification
methods are employed including the enhanced frequency domain decomposition and the stochastic subspace identification. The
identified modal parameters from the two methods are compared. Results show that modal frequencies and mode shapes from the
two methods are almost the same while the damping ratios are different. 相似文献
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本文通过分析和推导,在不考虑TE和TM模耦合影响后,用一网络等效表示双轴电介质加载对称双侧鳍线。将场问题转化为路问题,简化了特征方程的推导过程。在网络中使用理想变压器元件等效双轴电介质与各向同性介质分界面处的场匹配条件。最后对双轴电介质加载对称双侧鳍线的有效介电常数进行了数值计算。结果表明本文近似是合理的,有较高精度的数值解。 相似文献
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杰出的建筑师需要卓越的解决方案,新的卡诺尔大使馆建筑所面临的挑战之一就是批出最优方案,将由花岗岩制成的厚立面板安置在外墙的Poroton砖石上,高度复杂的立面结合复杂的建筑细部,它需要一种独特的解决方案。 相似文献
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对于一座建筑来说,在竣工的两年内就奠定其神圣的地位是一件非同寻常的事情,但是公正地讲,在Gateshead,坐落于Tyne & Weir的Sage音乐大厅,关于它的一切都是不同寻常的。 相似文献