检索结果-南通市图书馆

Non-uniform temperature distribution of the main reflector of a large radio telescope under solar radiation

Research in Astronomy and Astrophysics 2021年第11期21卷 233-242页

作者： Shan-Xiang Wei De-Qing Kong Qi-Ming Wang Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The non-uniform temperature distribution of the main reflector of a large radio telescope may cause serious deformation of the main reflector,which will dramatically reduce the aperture efficiency of a radio telescope.To study the non-uniform temperature field of the main reflector of a large radio telescope,numerical calculations including thermal environment factors,the coefficients on convection and radiation,and the shadow boundary of the main reflector are first discussed.In addition,the shadow coverage and the non-uniform temperature field of the main reflector of a 70-m radio telescope under solar radiation are simulated by finite element analysis.The simulation results show that the temperature distribution of the main reflector under solar radiation is very uneven,and the maximum of the root mean square temperature is 12.3℃.To verify the simulation results,an optical camera and a thermal imaging camera are used to measure the shadow coverage and the non-uniform temperature distribution of the main reflector on a clear day.At the same time,some temperature sensors are used to measure the temperature at some points close to the main reflector on the backup structure.It has been verified that the simulation and measurement results of the shadow coverage on the main reflector are in good agreement,and the cosine similarity between the simulation and the measurement is above 90%.Despite the inevitable thermal imaging errors caused by large viewing angles,the simulated temperature field is similar to the measured temperature distribution of the main reflector to a large extent.The temperature trend measured at the test points on the backup structure close to the main reflector without direct solar radiation is consistent with the simulated temperature trend of the corresponding points on the main reflector with the solar radiation.It is credible to calculate the temperature field of the main reflector through the finite element method.This work can provide valuable references for studying the thermal deformati

关键词： large radio telescope finite element analysis solar radiation shadow coverage temperature distribution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Back Frame Optimization of a large radio telescope Based on Force Cone Method

引用

Wuhan University Journal of Natural Sciences 2022年第5期27卷 424-438页

作者： WU Qinglong YAO Zhan WU Tanhui FANG Houfei HOU Yangqing Shanghai YueSheng Information Technology Co. Shanghai 201108China

A new research perspective is proposed to optimize the topology of truss structure by force cone method,which involves force cone drawing rules and growth rules.Through the comparison with the mature variable density topology optimization method,the effectiveness of force cone method is verified.This kind of new method is simple and easy to understand(no need to master complex structural optimization design theory).Besides,it is time-saving in finite element calculations,and can obtain an optimized truss layout easily.By drawing the force cone,its application on a large radio telescope’s back frame structure shows that,compared with the existing one in terms of structural stiffness,Root Mean Square(RMS)precision,and beam stress distribution,the optimized back frame using the force cone method has higher stiffness,better RMS,more uniform stress,and lighter weight.

关键词： large radio telescope back frame force cone method topology optimization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Reverse-Design Strategy for the Track Error of the Qi Tai telescope Based on Pointing Accuracy

引用

Engineering 2022年第6期8卷 209-216页

作者： Na Li Baoyan Duan Xiangyang Li Bin Zheng Jiang Wu Key Laboratory of Electronic Equipment Structure Design Ministry of EducationXidian UniversityXi’an 710061China

The Qi Tai telescope(QTT),which has a 110 m aperture,is planned to be the largest scale steerable tele-scope in the world.Ideally,the telescope’s repeated pointing accuracy error should be less than 2.5 arc seconds(arcsec);thus,the telescope structure must satisfy ultra-high precision requirements.In this pur-suit,the present research envisages a reverse-design method for the track surface to reduce the difficulty of the telescope’s design and manufacture.First,the distribution characteristics of the test data for the track error were verified using the skewness coefficient and kurtosis coefficient methods.According to the distribution characteristics,the azimuth track error was simulated by a two-scale model.The error of the long period and short amplitude was characterized as large-scale and described by a trigonometric function,while the short period and high amplitude error was characterized as small-scale and simulated by a fractal function.Based on the two-scale model,effect of the error on the pointing accuracy was deduced.Subsequently,the relationship between the root mean square(RMS)of the track error and the RMS of the pointing accuracy error of the telescope was deduced.Finally,the allowable RMS value of the track error was derived from the allowable pointing accuracy errors.To validate the effectiveness of the new design method,two typical radio telescopes(the Green Bank telescope(GBT)and the large Millimeter telescope(LMT))were selected as experimental examples.Through comparison,the theoretical calculated values of the pointing accuracy of the telescope were consistent with the measured values,with a maximum error of less than 10%.

关键词： Reverse design Track error large radio telescope Two-scale model Pointing accuracy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

ACTIVE VIBRATION CONTROL SYSTEM OF FAST FEED SYSTEM BASED ON PMAC CONTROLLER

ACTIVE VIBRATION CONTROL SYSTEM OF FAST FEED SYSTEM BASED ON...

引用

2006年中国机械工程学会年会暨中国工程院机械与运载工...

作者： YE P.Q., ZHANG H., ZHENG R., YANG K.M., LIN B.J. Department of Precision Instrument and Mechanology, Tsinghua University, Beijing 100084, China

Active vibration control of the feed support system based on Stewart platform is essential for successfully constructing a Five-hundred-meter Aperture Spherical telescope (FAST). A flexible control sc

关键词： large radio telescope active vibration control motion controller RtLinux.

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：