基于实测结果与修正模型的输电塔架特性分析

Analysis of Transmission Tower Characteristics Based on Measured Results and Modified Model

针对目前输电塔架特性分析主要采用软件分析和结构有限元模型不能准确反映结构真实特性,导致分析结果不全面,存在偏差的问题,提出采用实际测量结果与模型优化后的软件分析结果相结合的方法对输电塔架进行特性分析.先设计了基于电阻应变片和RS485总线结构的输电塔架结构承载力检测系统,利用该系统对输电塔架进行不同工况作用下的应力应变检测;再提出了一种先采用待修正参数的最优值来表征模型偏差方法建立塔架初次优化模型,再利用ANSYS优化算法对初次优化模型进行二次优化的模型搭建方法,并利用有限元分析软件ANSYS对优化后的输电塔架结构进行不同风速和不同覆冰厚度下的结构特性分析,最后结合测量数据从动态特性、稳定性及局部杆件应力等方面对系统结构进行了安全评估.分析结果表明使用实际测量与软件分析相结合的方法能更准确的对塔架结构特性进行评估,经对比优化前后模型固有频率最大相对误差不超过0.27%,表明用待修正参数的最优值来表征模型偏差和ANSYS优化算法相结合的模型修正方法,可有效提高结构建模的可靠性,修正后的模型可更有效的表征真实结构实际特性.

Since the software analysis and the structural finite element model cannot accurately reflect the real structural characteristics which result in the analysis results are incomplete and biased,the method of combining the actual measurement results with the software analysis results after model optimization is proposed to analyze the characteristics of the transmission tower.Firstly,a test system based on resistance strain gauge and RS485 bus structure is designed to test the stress and strain of the transmission tower under different working conditions.Then a method is proposed to establish the primary optimization model of the tower by using the optimal value of the parameters to be modified to represent the model deviation,and ANSYS optimization algorithm is used to set up the model for the secondary optimization of the primary optimization model.In addition,finite element analysis software ANSYS is used to analyze the structural characteristics of the optimized transmission tower structure under different wind speeds and different icing thicknesses.Finally,the system structure is evaluated in terms of dynamic characteristics,stability and local stress of bars.The results show that method of combining the actual measurement and analysis software can evaluate the tower structure characteristic more accurately.After comparison and optimization,the maximum relative error of the natural frequency of the model did not exceed 0.27%.It is shown that the model modification method combining model deviation and ANSYS optimization algorithm with the optimal value of the parameters to be modified can effectively improve the reliability of structural modeling,and the modified model can more effectively represent the actual characteristics of the real structure.