格构式输电塔顺风向抖振响应气动导纳函数研究

In current wind engineering practice, the numerical calculating method on along wind buffeting response of lattice transmission towers is widely used for solving practical engineering problems. Because of the application of strip and quasi-steady assumptions, the model of along wind forces on lattice transmission towers is directly derived from the wind velocity spectrum by neglecting the contribution of aerodynamic admittance function (AAF). Actually, there is much difference between wind velocity spectrum and wind force spectrum of lattice towers in along wind direction, and the AAF describes the spatial and temporal transfer function from the turbulent wind velocities to the buffeting forces acting on structures, the numerical simulating wind forces and wind-induced response analysis of the transmission towers will be lead to large errors if the contribution of AAF is neglected.. Considering the lattice transmission towers’ own structural characteristics, this project plans to have an extensive and careful study about the AAF of lattice transmission towers using the methods of theoretic analysis and wind tunnel test based on high-frequency-force-balance technique. The effects of several important parameters such as the incoming wind conditions, structural shapes and so on are considered. And the empirical expressions of AAFs for lattice transmission towers will be proposed to fit the test results. In addition, in order to verify the validity and reliability of the empirical expressions, aeroelastic models of the typical transmission tower system are tested in the wind tunnel; the AAFs will be identified from the wind-induced responses and be compared with the empirical expressions. The research will provide references for precise along wind buffeting response analysis of lattice transmission towers.

采用数值方法由风速模拟风荷载进行输电塔结构顺风向抖振响应计算分析已较为广泛的应用于解决工程实际问题。该方法在风荷载模拟中通常不考虑气动导纳函数的影响，气动导纳函数表征了脉动风速与抖振力之间的传递关系，忽略气动导纳的影响将导致模拟得到的风荷载和响应分析结果与实际情况存在较大误差。. 本课题在考虑输电塔结构特点的基础上，拟通过理论分析和高频天平测力风洞试验，对格构式输电塔顺风向气动导纳函数进行研究，分析来流条件、结构外形等参数对气动导纳函数的影响，建立基于测力试验的气动导纳函数经验表达式。并通过典型输电塔气弹模型测振试验，识别结构的气动导纳函数，验证经验公式的可靠性及准确性，为格构式输电塔结构精确顺风向抖振响应分析提供更为完整的数据基础和理论参考。

强风作用下格构式结构的破坏时有发生，说明现阶段对此类结构风荷载和动力响应特性认识仍存在较大不足。本课题首先通过高频天平测力风洞试验的方法，详细探讨了作用于单排（平面）桁架、典型多回路输电塔横担结构的风荷载特性，研究了结构体型系数随来流条件、风向、挡风系数等参数的变化规律；其次，采用整塔气弹模型风洞试验，研究了风场、塔型等因素对结构风致响应的作用，分析了不同响应对结构风振系数的影响。通过试验结果与国内外荷载规范的对比，总结了相关参数的合理取值及可能的简化方法，为准确获得格构式结构风荷载及我国荷载规范的修订提供试验参考及理论依据。最后，基于上述风洞试验结果，尝试建立适合描述格构式结构气动导纳函数的表达式，为格构式结构精确顺风向抖振响应分析提供依据。