Aeroelastic Model Test Study On Wind-induced Response Of Four Split Long Transmission Line

The long-span transmission tower-line system is an important lifeline project.The system has the characteristics of high tower structure,long-span,and this kind of structural system is sensitive to the response of wind load,and it is easy to occur dynamic collapse damage.the theoretical research on the wind resistance theory of the tower line system is not perfect at present,the inverted tower event also occurs.Therefore,the research on dynamic characteristics and wind-induced response of longspan transmission line system is particularly important for wind resistant design of transmission tower-line system.In this paper,the aerodynamic characteristics and wind vibration response of four split traverse,single span and double span,are studied on the test wire JL/G3A-1250/125.It also points out the shortcomings of the present research and puts forward some prospects.The work of this paper mainly includes the following aspects:(1)The background and object of research on wind-induced dynamic response of long-span transmission tower line system are introduced.Then,the characteristics of wind and the effect of wind on structure are described.Next,the research status of wind-induced response of transmission tower line is summarized.(2)The static action part of cable is analyzed systematically,including the analysis of the initial self weight state,the deformation coordination equation,the influence line function and the stiffness analysis.An example is also given.(3)On the principle of transmission line aeroelastic model test and the test of the system are introduced,analyzed the characteristics of the fluid,similarity principle and similarity criterion,analyzes the design of the standard model and distorted model,gives the model of dynamic characteristics and wind-induced response,also the wind tunnel test program are introduced.(4)Taking the wind tunnel test of single span transmission line as an example,dynamic response analysis based on modal displacement is carried out,including background response,resonance response and total response.A comprehensive and systematic comparison between theoretical analysis and experimental results is carried out,and some conclusions are drawn.(5)Taking the wind tunnel test of two span transmission lines as an example,the test mode,dynamic tension power spectrum,support reaction force,resistance coefficient,structure and aerodynamic damping ratio are analyzed.The main conclusions of this paper are as follows:1.The aerodynamic damping ratio generally increases with the increase of the wind speed for the theoretical calculation and the measured.But the measured aerodynamic damping ratio in-plane or out of plane is smaller than the theoretical calculation.2.The background component of the theoretical calculation of the along-wind dynamic tension is between the 61%~83% of the total measured response,the proportion of the background component is very large,and the proportion of the background component has a certain fluctuation.3.For the along-wind dynamic tension,the proportion of the background components were fitted with three Hermite polynomial interpolation in the total response is between 72% and 91%,it is a little larger than the results of theoretical calculation,but the fluctuation is smaller;the measured first order resonance component accounts for 4.5% to 11% of the total response,while the rest of the resonance component accounts for 3.9% to 11%.4.The measured background component,resonant component,and total response will increase with the increase of wind speed,and the background and total responses of theoretical calculation increase with the increase of wind speed.But,the proportion of the resonance component is not obviously related to the wind speed,and the ratio of the total theoretical response to the measured total response decreases with the increase of wind speed.