拿井线钢结构塔架覆冰荷载效应研究(任务书,开题报告,论文19000字)
摘要
近年来，随着社会的进步，电力在社会生活中占据了越来越重要的位置。在我国大力发展电力行业的同时，越来越多的输电塔架在全国各地建造起来。输电塔架是支承架空输电线路导线和地线并使它们之间以及与大地之间保持一定距离的塔形的构筑物。输电塔架的结构安全是输电线路正常工作的保证。我国长江流域是典型的覆冰区域，在2008年1月持续20多天的低温雨雪天气中，湖南等地大部分输电塔架发生了覆冰事故，导致很多钢结构杆塔严重破坏甚至倒塌。输电塔作为一种典型的钢结构高耸塔架，其高柔特性使得它在强烈覆冰荷载作用下的结构反应较为显著。而且输电塔架在覆冰厚度过大的荷载作用下的结构性失稳，是造成2008年雪灾倒塔事故的重要原因，为了减少或避免倒塔事故再次带来的巨大经济损失，对输电塔进行覆冰荷载效应研究是维护电网系统和日常输电线路安全运行的必要课题。为了保证我国输电线路铁塔结构在冰冻雨雪等恶劣气候环境条件下正常运行，同时也为了适应我国经济发展的需要，研究我国输电钢结构杆塔在覆冰荷载下的效应，是非常有必要的，具有重要的理论意义和工程使用价值。
国内外许多学者对钢结构塔架在覆冰荷载作用下受力性能做了深入的研究，大部分研究是在覆冰的基础上研究风荷载对钢结构塔架的影响。在覆冰的影响下，钢结构塔架的承载能力严重下降。因此，本文主要运用SAP2000软件建立输电杆塔的塔线体系模型，进行塔线体系的模态分析，分析输电塔的固有振动特性。本文主要研究输电塔线体系导线在不同覆冰厚度的情况下，输电杆塔的受力性能，分析其在覆冰荷载下的位移变形和内力，并研究在覆冰拆地线下，输电杆塔的承载力变化特点和规律。
关键词：输电塔；有限元分析；覆冰荷载；静力性能；缺线输电塔
Abstract
For the recent years, electricity has occupied a more and more important position in social life with the development of society. As the electric power industry develops rapidly in China, a growing number of transmission towers have been built all over the country. Transmission line tower is a tower structure supporting overhead transmission line conductor and ground wire, and keeping the distance between them and the earth, the structural security of which guarantees the normal operation of transmission line. The Yangtze river basin is a typical icing area in China. For over 20 days of low-temperatured, rainy and snowy weather in January 2008, ice coating accidents fell upon most transmission towers in Hunan and other places, causing the serious damage or even collapse of many steel structure towers. As a typical high steel structure, the high and soft feature of the transmission tower makes the structure respond violently under heavy ice load. Besides, the structural instability of transmission tower under the load of overly thick ice is the important reason of tower-falling accidents in the snow disaster of 2008. In order to reduce or avoid the next great economic loss caused by tower-falling accidents, the study on the effect of ice load upon transmission tower is a necessary project to safeguard the safe operation of grid system and daily transmission line. In order to ensure the normal operation of transmission line tower structure in freezing rain and snow weather conditions , and so as to adjust to the need of economic development in China at the same time, the research of steel structure tower’s response under ice load is strongly necessary, and has importance in theory and applied value of engineering.
Many scholars at home and abroad have deeply studied the mechanical performance of steel structure tower under ice load and most studies are about the effect of wind load on steel structure tower based on the ice load. Under the influence of ice coating, the bearing capacity of steel structure tower seriously declines. Therefore, this paper mainly uses Software SAP2000 to establish transmission tower model, carry out the modal analysis of transmission tower and analyze the inherent vibration characteristics of transmission tower. This paper mainly studies the mechanical performance of transmission tower under different thicknesses of ice load, analyzes its displacement deformation and internal force under ice load, and studies the characteristics and laws of the bearing capacity change of the transmission tower.
Keywords: transmission tower, finite element theory, ice load, static property, transmission tower without ground wire.
目录
第一章绪论 1
1.1引言 1
1.2 #59塔的基本信息 1
1.3 国内外的研究成果 3
1.4 本文主要内容 4
第二章输电杆塔的结构分析方法 5
2.1引言 5
2.2 有限元理论 5
2.2.1 基本概念 5
2.2.2有限元分析的目的 5
2.2.3有限元分析的步骤 6
2.3 输电杆塔结构分析方法 7
2.3.1 基本原理 7
2.3.2空间梁单元 8
2.3.3空间杆单元 10
2.3.4 约束条件 11
2.4 非线性有限元分析 12
2.4.1理论基础 12
2.4.2 屈曲问题 15
2.4.3 P‒Δ问题 16
2.4.4 大位移问题 16
第三章输电塔有限元模型建立及动力特性分析 18
3.1 输电塔有限模型的建立 18
3.2 输电塔的动力特性分析 18
3.2.1引言 18
3.2.2 输电杆塔的动力特性分析 19
第四章钢结构塔架覆冰特性分析计算 23
4.1 引言 23
4.2 影响输电线路覆冰的因素 25
4.2.1 影响导线覆冰的气象条件 25
5.2.2 地形及地理条件的影响 25
4.2.3 走向及悬挂高度对覆冰的影响 26
4.2.4 电场强度对覆冰的影响 27
4.3 输电导线覆冰的原因和种类 27
4.4 导线覆冰物理模型的建立 28
4.4.1 输电导线数值模拟计算 28
4.4.2 输电导线计算理论 29
4.4.3 输电导线有限元计算方法 31
4.5 输电塔结构覆冰工况分析 33
4.5.1 输电导线的内力大小和方向 36
4.5.2 输电塔线体系在覆冰荷载下的研究 38
4.5.3 输电塔线体系覆冰荷载效应分析 43
第五章结论与展望 48
5.1 结论 48
5.2 展望 48
参考文献 50
致谢 52
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