| The air supported membrane structure is a large-span spatial structure formed by using indoor and outdoor pressure difference forming with the advantages of light weight,large span,beautiful appearance and fast construction speed.With the emergence of haze weather in the north and the increasing demand in actual production,the air supported membranes were more and more widely used.The membrane structure is a flexible structure that is sensitive to wind and the wind load is considered as a control load in the design.With the use of the air supported membrane,damage has also appeared,but at that time,the wind speed displayed has not reached the design wind speed.The main reason is that the wind and the rain appeared simultaneously,and the rain cause the wind field around the membrane surface to suddenly change,the strong wind-driven rain causes damage.In order to ensure the healthy use of the membrane structure,the studies about the combined action of wind and rain on the air supported membrane structure were done,and the results can provide useful guidance for future structural design.Firstly,the wind load is taken as the gaseous state and the raindrop is used as the liquid state with the characteristics of wind and rain.Based on the Eulerian model of multiphase flow theory,the wind and rain interaction model were established.Secondly,three kinds of inflatable membrane structures(30m×20m×5m,80m×50m×15m,130m×100m×25m)are established.The fluid domains of the three models were analyzed by Fluent,and the reasonable fluid domains of each model are determined to be 450m×200m×60m,550m×400m×150m,640m×500m×250m.The three models under different wind direction angles were analyzed.According to the maximum value of wind pressure coefficient,the model analysis wind direction angles were 0°,50°and 60°.Then considering a variety of working conditions: wind speed selection of 10m/s,18m/s and 30m/s,rain intensity selection of 40mm/h,70mm/h and 130mm/h,through cross combination,the combination of wind and rain realized.Finally,the corresponding wind pressure coefficient is obtained by FLUENT,and the structural response is analyzed.The results show that the mechanical properties of the wind and rain are significantly changed compared with the pure wind.The greater the span of the structure,the greater the influence of wind speed and rain intensity.Because of the displacement on the second and third inflatable structures is too large,the structure optimization design is carried out by increasing the internal pressure of the model to reduce the membrane surface stress to a reasonable range.These studies have certain guiding significance for the design of large-span inflatable membrane structure. |
