【作者】 汪之松；

【导师】 李正良；

【作者基本信息】 重庆大学 ， 结构工程， 2009， 博士

【摘要】 输电塔线体系是风敏感型结构体系,风荷载是输电塔结构设计的控制荷载。目前,对特高压输电塔的风荷载模型、考虑塔线耦联的风振响应规律以及风振的灾害研究尚处于初期。本文以拟建的1000kV双回路特高压输电线路为背景,对特高压钢管输电塔的风荷载模型、风致振动特性、塔线耦合体系气弹性风洞试验以及风振疲劳等问题展开研究,主要包括以下几方面内容:(1)基于HFFB试验确定输电塔的风荷载谱。由静力三分力风洞试验得到钢管输电塔的体型系数;对输电塔半刚性模型的HFFB试验结果进行处理,去除了基底弯矩谱中共振响应的影响,并对处理后的弯矩谱进行拟合,得到各风向角下的顺风向、横风向及扭转向的基底弯矩谱公式。基于风荷载竖向相干性与风速相干性一致的假设,得到输电塔不同高度的风荷载自谱与互谱,并分析输电塔横风向激励的组成,识别出紊流激励部分与旋涡脱落激励部分约各占一半。(2)通过气弹性风洞试验研究双回路特高压钢管输电塔及塔线体系的风振响应特性。采用半刚性节段加“U”形弹簧片的方法设计制作输电塔的气动弹性模型,动力特性测定表明按此方法制作的模型满足气弹性风洞试验的要求。对塔线体系气弹性风洞试验时输电塔与导线采用不一致比例的问题进行数值分析,从理论角度论证了这一方法的可行性。由气弹性风洞试验结果总结了双回路特高压输电塔及塔线体系的风振响应特性,并通过试验结果反演得到了结构的固有特性和系统的输入激励。(3)建立塔线体系的有限元模型,分别在时域和频域对塔线耦合体系的风振响应进行理论分析,得出的结果与风洞试验吻合。推导了三节点索单元以及考虑摆动刚度的绝缘子单元的刚度与质量矩阵。在等效线性化的基础上对塔线体系的风振响应进行频域分析,结果表明导线张力较大、垂度较小时,塔线体系的频域计算结果也能达到较高的精度。(4)采用等效静力风荷载组合法和风振系数法计算输电塔的等效静力风荷载,为设计中考虑横风向影响提出建议。试验结果均表明,输电塔在横风向的风振响应与顺风向的动力部分在同一个数量级。为考虑输电塔横风向的等效静力风荷载,引入广义阵风效应因子和广义风振系数,为输电塔抗风设计中考虑横风向风振效应提供方便、合理的方法。(5)基于线性疲劳累积损伤理论,在时域与频域讨论输电塔结构的风振疲劳寿命的计算,提出估算输电塔风振疲劳的思路和方法。通过输电塔的风振时程分析和雨流计数法在时域中计算结构的风振疲劳累积损伤,并比较目前频域内计算疲劳累积损伤的各种方法,结果表明频域估算疲劳寿命偏于保守,其中等效应力法计算结果与雨流法最为接近,计算过程也较为简单方便,比较适用于基于全寿命周期的输电线路设计。更多还原

【Abstract】 Transmission tower-line is a type of wind-load-sensitive structure , and wind load is the main control load. At present, the studies of the wind load model on the system, the response regulation and disaster induced by wind load are still at the initial stage. Therefore, based on the two-circuit 1000kV UHV power transmission line under planning, the wind load model on the steel tube tower, the wind-induced vibration character, the aeroelastic wind tunnel test of the tower-line coupled system and the estimate of the fatigue cumulative damage caused by wind-induced vibration are discussed as follows:(1) The wind load spectrum is formulated through the HFFB test. The shape coefficient of the two-circuit UHV steel tube transmission tower is obtained by the three-component-force test; and after the resonance response in the results of the HFFB test of the semi-rigid model of the lattice type tower is filtered, the foundation moment spectrum in the along-, cross-wind and torsion direction under different wind angles is fitted to formulation. Assumed that the coherence of the wind load in vertical is the same to the wind speed, the auto power spectrum and cross power spectrum of the wind load on the tower is formulated. Futhermore, the analysis shows that the contribution of the turbulence is about equal to the vortex shedding for the cross-wind motivation.(2) The wind-induced vibration of the steel tube transmission tower-line coupled system is studied by the aeroelastic wind tunnel test. The aeroelastic model is designed and made by the semi-rigid segment and U shape spring, and the checking result shows that the aeroelastic model meets the requirments of the wind tunnel test. As the tower and conducting cable can not use the same scaling factor, the distorted model is proved by numerical analysis. The character of wind-induced response of the the tower and tower-line system is summarized from the results of wind tunnel test, and the structure’s natural characteristics and the input motivation is obtained from response inversion.(3)After building the finite element model of the tower-line coupled system, the analysis is conducted in both time-domain and frequency-domain numerically, and the response rules of single tower and tower-line system agree well with the results obtained from aeroelastic model tunnel test. The stiffness- and mass-matrix of the three-node- cable element and the insulator element considering the swing stiffness are deduced. With the assumption of equivalent linearization, the systems wind-induced respons are analysized in frequency-domain, and the result shows that the analysis in frequency-domain is accurate while the cable is tensioned and the sag is small.(4) The equivalent static wind load is calculated by the load combination method and wind vibration coefficient method respectively, and the suggestion is advanced for the consideration of cross-wind load in the design. The results of the test indicats that, the wind-introduced responses in the along-wind direction equals to that in the cross-wind direction. In consideration of equivalent static wind load in the cross-wind vibration, the generalized gust factor and wind vibration coefficient are introdued to calculate the cross-wind vibration in design.(5) Based on the liner fatigue cumulative damage theory, the transmission tower’s fatigue life under wind-indced vibration is calculated in the time-domain and frequency-domain, and the process and method for the analysis of the tower’s wind-indced fatigue is proposed. By the time-history analysis of the tower structure and rain-flow method, the fatigue cumulative damage is calculated in time-domain. According to the comparison of differernt existing methods in frequency-domain, generally all of the methods are conservative in estimation of the fatigue life, and the result of equivalent stress method is silmilar to that of the rain-flow method. Because of its simplify in calculation, the equivalent stress method is more suitable in transmission tower’s total life cycle design.更多还原