| Large-span building membrane structure has been widely used in various public buildings in recent years because of its changeable and novel shape.The large span building membrane structure has light weight,large flexibility and obvious non-linearity.The main control load is wind load,which is also one of the main reasons for the broken building membrane structure.Wind load can be divided into horizontal wind and vertical wind.Most traditional rigid building structures only consider the effect of horizontal wind load,but for large-span building membrane structure,the response of the structure under horizontal wind load is perpendicular to the membrane structure surface,close to the vertical.At the same time,the response direction of the membrane structure surface under vertical wind is the same as that caused by horizontal wind,so the wind vibration response of the membrane structure will increase under vertical wind,resulting in a sharp increase in the risk of membrane structure damage.Therefore,the effect of vertical wind load can not be ignored in the wind-resistant design of long-span membrane structures.An in-depth study on the wind pressure distribution characteristics of long-span membrane structures under the action of vertical wind is of great theoretical significance and engineering value to the wind-resistant design of long-span membrane structures.Based on the large eddy simulation method,the computational fluid dynamics theory and the Fluent platform,the wind pressure characteristics of typical large-span membrane structures under vertical wind loads are studied in depth.The main research contents are as follows:(1)The average wind pressure distribution of typical large-span membrane structures under vertical mean wind loads is studied.A user-defined program(UDF)on Fluent platform was used to realize the generation of inlet turbulence.The wind pressure characteristics of a membrane structure canopy were studied by using the large eddy simulation method,and the results were compared with the experimental results,which verified the correctness of the large eddy simulation method to calculate the wind pressure of the membrane structure.The typical saddle-shaped,wave-shaped and continuous arch membrane structures were studied.The average wind pressure distribution of three kinds of large-span membrane structures under vertical wind under 27 working conditions,including different wind speeds and wind angles,considering the two-way fluid-structure coupling effect,was studied.The wind pressure distribution law of roof surface under each working condition was obtained,and the corresponding results were compared with those under horizontal wind.The average wind pressure distribution on the roof surface of large-span membrane structures with different shapes under vertical average wind load is analyzed and summarized.(2)Based on the large eddy simulation method and program mentioned above,the wind vibration response and wind pressure zoning of three typical types of long-span membrane structures subjected to vertical pulsating wind were studied.Considering the two-way fluid-structure coupling effect,the wind-vibration responses of three different types of large-span membrane structures(wave-shaped,saddle-shaped and continuous arch)under the most unfavorable wind Angle and different wind speeds were studied,and the zoning coefficients of fluctuating wind pressure of large-span membrane structures with different shapes were defined.(3)The common saddle and arch membrane structures were selected as the research objects.Considering the two-way fluid-structure coupling effect and based on the streamline design concept,the aerodynamic performance improvement of the optimized model was systematically analyzed from many aspects,such as wind vibration response,displacement change,velocity vector change and wind pressure change.The main conclusions obtained in this article are as follows:(1)Under the action of 0° vertical average wind load,it is found that the partial pressure coefficient of three kinds of membrane structure roof surface has a great influence.Compared with the wind pressure coefficient of membrane structure roof surface under the action of 90°horizontal wind load,its value is obviously larger.Under the action of horizontal wind,only the dynamic pressure part of the wind on the membrane structure surface has an effect on the membrane surface.Under the action of vertical wind,the hydrostatic part and dynamic pressure part act together on the surface of membrane structure.The results show that the surface of membrane structure is obviously affected by vertical wind load.(2)Under the most unfavorable wind direction Angle,the wind vibration response frequency of membrane structure surface under the action of vertical fluctuating wind load is intense,and the effect of vertical fluctuating wind is obvious.It is found that the wind vibration response effect of large-span membrane structure roof surface is related to the building structure form.The proposed zoning values of the wind pressure coefficient on the surface of the membrane structure are given.(3)The aerodynamic performance of the optimized model is significantly improved,and the fluctuation range values of the wind vibration response are significantly decreased,indicating that the air flow on the surface of the membrane structure becomes stable,thus improving the service cycle of the membrane structure and extending the life of the membrane structure.There are 55 figures,2 tables and 65 references in this paper... |
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