【作者】 柳国环；

【导师】 李宏男；

【作者基本信息】 大连理工大学 ， 防灾减灾工程及防护工程， 2010， 博士

【摘要】 输电塔-线体系兼有质轻、高柔、大跨和小阻尼等特点,对风荷载十分敏感。输电线路的风致破坏现象时有发生。当前,对于格构式输电塔的具体抗风设计方法以及输电塔-线体系的风振响应均处于研究阶段,尚未建立起一个包括细节在内且公认有效的具体实施方案,甚至关于格构式输电塔横风向振动的作用机理还仍处于探讨阶段,尚未有统一定论。本文从指出并完善广义气动力谱理论公式的固有缺陷入手,并通过三种典型格构式输电塔气动弹模型的风洞试验,主要对格构式输电塔横风向振动的作用机理、风振激励模型、位移响应实用计算模型以及内力响应新的计算方法等方面作了系统性研究。通过研究,不仅对横风向振动的作用机理有了更为清晰的认识,同时还为格构式输电塔风振响应计算提供了一个参数明确、实用性强且更加方便快捷的可行性实施方案；此外,通过三种典型格构式输电塔-线体系的风洞试验,对输电塔-线体系研究对象的合理选定、中塔(气动弹塔,下同)的风振特性及其风振响应规律等方面进行了研究,其中的部分内容具有“首次”和“发现”意义。本文工作主要包括如下几个方面：(1)明确指出了当前消除基底力矩一阶振型共振贡献理论公式的固有缺陷,并对该公式进行了理论完善。首先,明确指出当前消除基底力矩一阶振型共振贡献理论公式的固有缺陷；然后,引入理应客观存在的且能够体现输入与输出相关性的交叉项,明确交代了具体推导过程,从而推导出相应的计算公式；进一步,明确指出了由此公式得到的广义力谱是已包括了气动阻尼在内的广义气动力谱,并给出物理解释和有助于理解的理论说明。因此,可不必为此对气动阻尼再进行评估。(2)全面且深入考究了格构式输电塔横风向振动的作用机理。首次明确指出了高频漩涡脱落在性质上的存在性及其在量化上的可忽略性；深入并全面分析了格构式输电塔横风向振动诱因,由此可知横风向振动是由于来流风与格构式输电塔相互作用过程中产生了一种垂直于来流方向的大尺度尾流所致,从而考证了邹良浩博士在结论层面上的研究结果；对紊流场与均匀流场试验结果进行对比分析,进而明确指出：紊流场中诱发格构式输电塔横风向振动的大尺度尾流主要是由于来流风中的脉动成分所致,而不是均匀流。这一点,使得对格构式输电塔横风向振动诱因的认识又更进了一步。(3)提出了求解格构式输电塔构件内力的新途径—“位移加载法”,建立了风振激励模型并推导出了风振位移响应计算模型。基于本文气动弹模型风洞试验结果以及完善了的广义气动力谱计算公式,首先建立了一阶广义气动力谱实用计算模型,同时给出了各风攻角工况下的具体拟合参数和广义气动力均方差系数；然后,定义“位置矩阵”和“广义气动力谱振型系数”这两个关键性参数,进而推导出了高阶广义气动力谱模型表达式；为便于工程应用,进一步推导出了风振位移响应实用计算模型,该模型可考虑高阶振型的贡献；最后,提出了理论严格合理且现实可行的“位移加载法”求解输电塔构件内力的新途径,其突出优点是：可完全避免传统方法中需要建立等效静力风荷载的这一步骤。(4)深入研究并发现了格构式输电塔-线体系中塔风振响应的特性及其规律。首先,通过试验对比分析,指出了有必要将五塔四线体系作以研究中塔的风振响应；通过风洞试验,深入并全面考察风速与弧垂这两种可变因素分别对顺风与横风向位移响应的影响,通过分析得到了一致性的变化规律；深入考察风速对顺风与横风向位移功率谱的影响,通过分析得到了具有发现性质的规律,并通过经典理论对这一规律进行合理解释与说明,进而给出了合理性推断。这一规律,在输电塔-线体系试验研究结果层面上具有“发现”意义；图列出若干不同风速下中塔的位移响应平面运动轨迹及其随时间变化的空间位移轨迹,并对文中各种风速下的轨迹图进行对比和归纳,由此发现了具有一致性的确定性变化规律和特征,这一工作结果具有“首次”意义。更多还原

【Abstract】 Since transmission tower-line system is characterized by lightweight, tall, flexible, long-span and low damping, it is very sensitive to wind load. The wind-induced disasters in transmission tower-line system occur frequently. At the present time, the specific wind resistance design method for lattice transmission tower and study on wind-induced responses of transmission tower-line system are still in the process of research and there is not a well-known, effective and specific wind resistance program. Moreover, the exciting mechanism of cross-wind vibrations of lattice transmission tower are also in the explore stage and not be confirmed thoroughly.In this thesis, a theoretical deficiency inherent in the current formula for calculating generalized aerodynamic force spectrum is improved and the wind tunnel tests of the aeroelastic models for three typical lattice transmission towers are performed. In order to provide a practical, convenient and feasible program including the specific parameters, investigations on the exciting mechanism of cross-wind vibrations, wind loading model, model for calculating wind-induced displacement response including higher modal contributions, new approach for calculating wind-induced internal forces of tower and so on are systematically processed. Moreover, the reasonable subject investigated of transmission tower-lines system is selected through test analysis in order to get more reasonable analytical. results of middle tower(aeroelastic tower). Finally, the wind-induced responses are investigated and some regularity test results are firstly addressed. The main works are summarized in the following:(1) The theoretical deficiency inherent in the current formula for calculating generalized aerodynamic force spectrum is explicitly point out and improved. The correlation between input and output is sufficiently considered and the specific inducing process and improved formula are given explicitly. Then, it explains and emphasizes that the influence of aerodynamic damping force,in actuality, has been included in the formula. So, it is not necessary for the influence to evaluate the aerodynamic damping specially.(2) Intensive investigations and studies on the exciting mechanism of cross-wind vibrations are performed. It explicitly points out that the high-frequency vortex shedding does exist but its contribution to wind-induced displacement response is small and might be ignored. Then, the investigations on the reason of cross-wind vibration are intensively and comprehensively performed and the results show that it is a large-scale wake flow generated in the process of interaction between wind and transmission tower induces tower’s cross-wind vibration. The research result, in terms of conclusion, confirms the analysis result given by Dr. Zou Lianghao. Moreover, by comparing the test results obtained from uniform flow field and turbulent flow field, it points out that it is the fluctuating components, instead of the mean components, of turbulent flow field that generate the large-scale wake flow mentioned above,. The conclusion makes more progress for understanding the exciting mechanism of the cross-wind vibration.(3) A new approach to solve the internal forces of frame member of transmission tower is presented, and the calculating model of wind load and fomula for displacement response are separately deduced as well.. Based on the improved formula of fundamental mode generalized aerodynamic force spectrum and the results of wind tunnel test in this thesis, a practical model for calculating fundamental mode generalized aerodynamic force spectrum is established, and the corresponding fitting parameters and RMS deviation coefficients of generalized aerodynamic force are also given. Then, two new variables, location matrix and generalized aerodynamic force spectrum mode coefficient, are firstly defined, and a model for calculating higher mode generalized aerodynamic force spectrum in along-wind direction is further derived. Furthermore, a practical model for calculating alongwind-induced displacement response, including the contribution of higher modes, is deduced. Finally, a new approach named "applying load using displacement" is presented and proposed to solve the internal force of tower. The method is not only rational and feasible, but also avoids establishing the equivalent static wind loads.(4) Intensive test investigations on the wind-induced response of middle tower of transmission tower-lines system are performed and some new discoveries about the corresponding regularity are firstly addressed. It point out that it is necessary to select the system including five tower and four line segments as system investigated in order to get more reasonable test results. The influence of wind velocity and sag on along-wind and cross-wind displacement responses is investigated and analyzed comprehensively. Besides, the power spectrums of displacement responses in along-wind and cross-wind direction are further analyzed and it discovers some new phenomena which are not addressed in previous literatures. According to the phenomena, the rational explanation and further inference are given. Moreover, the plane and space motion path of displacement response under different wind velocity are also given. Through further analysis, the uniform variation regularity of the motion path, with the increase of wind velocity, is discovered and firstly addressed.更多还原