摘要
防风网是应环境保护要求而发展起来的一种新的结构型式。防风网结构在国内的应用才刚刚起步,在国内外也未见有关于它的动力响应以及风振疲劳分析的研究工作。虽然我国现已建成的防风网工程不多且规模较小,但是随着港口功能的扩展和人们环保意识的加强,大型、高效能的防风网会得到愈来愈广泛的应用。防风网结构的设计安全是面临的重要课题,特别是在风荷载作用下防风网结构的优化设计、结构动力特性、风振响应以及风振疲劳损伤等,是大型、高效能防风网结构设计需要解决的关键技术问题。
本论文以某实际工程为背景,对防风网结构的设计方法,风振响应分析以及风振疲劳特性等进行了研究。
本文的主要工作包括以下几个方面:
1、防风网结构设计方法研究。给出了防风网结构主要设计内容、方法和步骤。设计内容主要包括:防风网总平面布置、上部钢结构设计、基础结构设计等。结合某防风网的实际工程,进行了防风网结构设计。
2、风压力作用时程模拟。由《建筑结构荷载规范》中的Davenport脉动风速谱生成200s的脉动风荷载作用时程。
3、防风网结构静力有限元分析。按《建筑结构荷载规范》计算等效静风压,将等效静风压作用在防风网上,利用有限元方法对防风网结构的应力、位移进行静力分析。
4、防风网结构的动力特性研究。利用有限元方法计算防风网结构的频率、振型,得到防风网结构的第一阶振动频率为0.460,进一步对不同频率下防风网结构的动力响应特性进行分析。
5、防风网结构动力响应研究。将由脉动风速谱生成的脉动风荷载作用时程作为输入,利用有限元方法对防风网动应力、位移响应时程进行计算。结果表明,在风动力作用下防风网结构的应力、位移有较大的放大效应。
6、防风网结构风振疲劳分析。利用瞬态动力分析的结果,找出防风网结构应力疲劳最危险的地方。结合疲劳分析的基本理论,把应力时程谱转化成应力峰值谱,应用雨流法统计最危险单元的应力时程,得到应力循环次数及应力幅大小,基于Miner线性累积损伤准则编写Ansys的风振疲劳程序计算得到疲劳寿命。本文计算了设计风速为32.9 m/s、26.8 m/s、20 m/s和12 m/s时防风网结构的疲劳寿命。
The windbreak is a new structure developed for environmental protection. Its application in our country has just begun, and there is few research on its wind-induced dynamic responses and fatigue. Although the windbreaks we have built in our country were few and small-scale, with the expansion of port functions and the strengthening of environmental awareness, the large-scale and high-performance ones will be more widely applied. Thus structural design security of windbreak is an important subject we are facing, especially the structural optimization, wind-induced behavior, response and fatigue are the key issues need to be solved urgently.
This work is based on one practical project, including the design method of the project and analysis of the wind-induced responses and fatigue of the windbreak.
The main work includes the following aspects:
1, Research on the design method of the windbreak. The main content, methods and steps of design were introduced. The design mainly includes the layout of the windbreak, the steel structure design and the infrastructure design. And the structural design for a practical project was performed.
2, The simulation of the wind pressure. A fluctuating wind load of 200 seconds was generated by the Davenport spectrum according to the loading code for design of building structures.
3, The static FEM analysis of the windbreak. The wind pressure, supposed as invariable force, was calculated according to the loading code for design of building structures, and the displacements and stresses of the windbreak were calculated by the static finite element method.
4, The dynamic behaviors analysis of the windbreak. The frequency and vibration modes of the windbreak were calculated by the finite element method. The result shows that the first frequency of the windbreak structure is 0.460. Then the dynamic responses under different frequencies were analyzed.
5, The dynamic response analysis of the windbreak. The displacement and stress of the windbreak were calculated by the dynamic finite element method with the fluctuating wind load generated by the Davenport spectrum as input. The result shows that the stress and displacement of the windbreak structure are much larger under the dynamical force.
6, The wind-induced fatigue analysis of the windbreak. The most dangerous place of the structural stress was identified by the results of the transient dynamic analysis . According to the basic theory of fatigue, stress spectrum was converted into stress peak spectrum. We got the stress amplitude and the number of circulation by analyzing the process of the most dangerous element stress with the rain flow method and calculated the fatigue life of the windbreak based on the linear cumulative damage Miner theory by compiling the procedure of Ansys wind-induced fatigue. The fatigue life was calculated when the designed wind speed respectively is 32.9 m/s, 26.8 m/s, 20 m/s, and 12 m/s.
引文
[1]李玉江,吕焕更,在秦皇岛港8#、9#号煤码头设置防风网的论证研究,交通环保,4-5:35-37
[2]沈熹,防风网防尘技术在露天煤堆长的应用研究现状及对发展我国防风网防尘技术的建议,交通环保,1995,16(3):22-25
[3]陈凯,朱凤荣,钮珍南,防风网作用效果的风洞实验评估,北京大学学报(自然科学版),2006,42(5):636-640
[4]PARK CW,LEE SJ,Experimental study on surface pressure and flow structure around a triangular prism located behind a porous fence.J Wind Eng Ind Aerodyn,2003,91:165-184.
[5]YARAGAL SC,RAM HSG,MURTHY KK,An experimental investigation of flow fields downstream of solid and porous fences,J Wind Eng Ind Aerodyn,1997,66(2):127-140
[6]刘锡良,周颖,风荷载的几种模拟方法,工业建筑,2005,35(5):81-84
[7]Kareem A,Kijewski T,Time—Frequency Analysis of Wind Efects on Structures,Journal of Wind Engineering and Industrial Aerodynamics,2002,90:l 435~l 452
[8]吴筑海,马骏,周岱等,空间结构风时程模拟及分析,第四届全国现代结构工程学术研讨会论文集, 2004.456-462
[9]娇江,日本北海道的防风网,世界农业,1987
[10]赵海珍,梁学功,马爱进,防风网防尘技术及其在我国大型煤炭港口的应用与发展对策,环境科学研究,2007,20(2):67-71
[11]祁有祥,程复等,防风网防风效能初步研究,水土保持研究,2007,14(1):190-195
[12]林官明,叶文虎,防风网泄流区湍流的子波分析,北京大学学报(自然科学版),2003,39(5):734
[13]陈凯,朱凤荣,钮珍南,防风网作用效果的风洞实验评估,北京大学学报(自然科学版),2006,42(5):636-640
[14]张光玉,詹水芬,赵洪鑫,防风板抑尘效果数值模拟与风洞实验对比研究,水道港口,2007,8
[15]张亚青,张光玉,詹水芬等,港口煤炭堆场防风网防尘效果数值模拟研究,水道港口,2007,4
[16]张光玉,陈立,王奇志等,秦皇岛港堆场防风网风洞试验研究,交通环保,2003,2
[17]陈贤川,大跨度屋盖结构风致响应和等效风荷载的理论研究及应用:[博士论文],浙江;浙江大学,2005
[18]吴筑海,大跨度空间网格结构的风模拟与及其小波分析:[硕士论文],上海:上海交通大学,2005
[19]白泉,风速时程数值模拟研究:[硕士论文],辽宁:东北大学,2005
[20]中华人民共和国建设部,GB 50009-2001,《建筑结构荷载规范》,北京:中国建筑工业出版社,2002
[21]中华人民共和国建设部,GB 50007-2002,《建筑地基基础设计规范》,北京:中国建筑工业出版社,2003
[22]中华人民共和国建设部,GB 50017-2003,《钢结构设计规范》,北京:中国建筑工业出版社,2003
[23]中华人民共和国建设部,GB 50010-2002,《混凝土结构设计规范》,北京:中国建筑工业出版社,2002
[24]中华人民共和国交通部,JTJ 215-98,《港口工程荷载规范》,北京:人民交通出版社,1998
[25]中华人民共和国交通部,JIJ 283-99,《港口工程钢结构设计规范》,北京:人民交通出版社,1999
[26]丁阳,钢结构设计原理,天津:天津大学出版社,2004
[27]河海大学,大连理工大学,西安理工大学,清华大学,水工钢筋混凝土结构,北京:中国水利水电出版社,1996,第三版
[28]邱驹主编,港工建筑物,天津:天津大学出版社,2002
[29]金伟良,工程荷载组合理论与应用,北京:机械工业出版社,2005
[30]《轻型钢结构设计手册》编辑委员会,轻型钢结构设计手册,北京:中国建筑工业出版社,2006,第二版[31李星荣,钢结构工程施工图实例图集,北京:机械工业出版社,2006
[32]中国建筑标准设计研究院钢结构设计制图深度和表示方法,北京:中国建筑标准设计研究院,2003
[33]黄本华,结构抗风分析原理与应用,上海:同济大学出版社,2001
[34]顾明等,大跨度屋盖结构考虑模态耦合的抖振共振响应分析方法,振动工程学报,2006,6(2):179-183
[35]薛松涛,钱宇音等,风速谱的分析研究及风致响应的计算分析,工程力学,2001:194-198
[36]于峰,于薇薇等,杆系结构风激响应及谱分析,中国海洋平台,2004,19(1):20-25
[37]全涌,顾明.高层建筑横风向风致响应及等效静力风荷载的分析方法,工程力学,2006,23(9):84-88
[38]王元清,张勇等,拱型波纹钢屋盖结构风振响应的频域分析,北京交通大学学报,2006,30(4):31-34
[39]董伟智,张熙颖,基于ANSYS的大跨屋盖结构风振响应分析,吉林建筑工程学院学报,2006,23(3):16-20
[40]李立,李勇,集中风载下桥梁连续模型随机抖振分析,华东公路,2001,4(131):36-38
[41]周晓峰,董石麟,巨型钢框架在强风作用下的非线性时程分析,工业建筑,2001,31(6):61-63
[42]杨鑫炎,高耸结构抖振时域分析:[硕士论文],四川:西南交通大学,2005
[43]王世村,高耸结构风振响应和风振疲劳研究:[博士论文],浙江:浙江大学,2005
[44]武岳,考虑流固耦合作用的索膜结构风致动力响应研究:[博士论文],黑龙江:哈尔滨工业大学,2005
[45]屠海明,桅杆结构风振疲劳分析:[硕士论文],上海:同济大学,2000
[46]徐建波,桅杆结构风振响应及疲劳分析:[博士论文],上海:同济大学,2004
[47]何鹏飞,桅杆结构疲劳分析及振动控制:[硕士论文],上海:同济大学,2004
[48]董乐义,罗俊雨,流计数法及其在程序中的具体实现,计算机技术与应用,2004,24(3):38-40
[49]温应龙,桅杆结构随机风振疲劳及可靠性研究:[硕士论文],上海:同济大学,2004
[50]黄健,桅杆结构随机风振疲劳及控制研究:[博士论文],上海:同济大学,2004
[51]翁恩豪,空间网格结构整体疲劳分析的研究:[硕士论文],浙江:浙江大学,2005