Wind Induced Vibration Response Analysis And Vibration Suppression Of High Mast Light Poles Based On Two-Way Fluid-Structure Interaction

With the deepening development of urban construction in China,the application of high mast light poles is further expanded to meet the lighting needs of large public places.As a highly flexible structure,the high mast light pole is very sensitive to wind load in the natural environment due to the large aspect ratio.When the wind blows through the high mast light pole,the vortex shedding will be formed at the back of the structure.If the vortex shedding frequency is close to the vibration frequency of the structure,the high mast light pole will appear resonance phenomenon,resulting in the increase of vibration amplitude,which will increase the damage to the structure and even lead to structural damage,resulting in serious safety risks.Therefore,it is of great significance to study the wind vibration response and vibration suppression of high mast light poles.In this paper,the numerical simulation method is used to analyze the vibration response characteristics of the high mast light pole under different wind speed conditions,study the influence of different outer helical strakes on the wind vibration response of the high mast light pole,and obtain the relationship between the pitch P,the height H,and the vibration control effect of the structure.The main research contents and conclusions are as follows:(1)The ANSYS Workbench was used to establish a numerical calculation model.The numerical simulation analysis shows that the high mast light pole structure has obvious cross-wind vortex vibration in the wind speed range of 5～8 m/s.The vortexinduced vibration phenomenon is most significant when the incoming wind speed reaches 6 m/s.In this case,the third mode mainly affects the vortex-induced vibration.(2)The wind vibration response of the high mast light pole is controlled by adding helical strakes.The research results show that the external helical strake can amplify the along-wind response of the high mast light pole to a certain extent,it has a significant inhibitory effect on the cross-wind vortex-induced resonance response.(3)The optimal pitch P is found by controlling the same height H of the helical strake.The research conclusion is as follows:with the decrease of the pitch P of the external helical strake,the along-wind response of the high mast light pole increases to a certain extent,and it has a certain restraining effect on the cross-wind response of the high mast light pole.When the helical strake with the same height is adopted,the smaller the pitch is,the better the effect of suppressing the high mast light pole’s vibration.When the pitch P is 7.5D(D is the critical diameter of the third mode),the vibration suppression effect is much better.and the optimal pitch P=7.5D is chosen.(4)The optimal height H is found by controlling the pitch P to be the same.The research conclusion is that:with the increase of the height H of the external helical strake,the additional helical strake will amplify the along-wind response of the high mast light pole to a certain extent and has a certain inhibitory effect on the cross-wind response of the high mast light pole.When the pitch P is the same,the higher the height of the outer helical strake is,the better the vibration suppression effect of the high mast light pole is.However,if the height is too high,it will have an excessive adverse effect on the along-wind response of the structure.After a comprehensive comparison,the height H=0.20D is selected as the optimal parameter.