Research On Construction Simulation And Inflatable Forming Technology Of Tensairity Dome

The Tensairity is a new type of structural system proposed in recent years,It uses different forms of inflatable gasbags instead of the vertical struts of the traditional cable supported structure.The Tensairity is simple,its load-transferring rout is clear and construction is simple,these advantages make it get the general attention and research of scholars,and develop rapidly from cable supported plane structure to cable supported spatial structure,the latter is this paper’s main research object.(1)In order to establish the pre-inflatable folding model of flexible gasbag,this paper presents a new method of establishing folding model of gasbag-simplified reverse folding method(SRF)based on the predecessors’ works.A large number of examples show that the method is simple and convenient and the model has the high accuracy.So SRF is a feasible method of airbag folding modeling.(2)This paper studies the simulation method of gasbag inflation-the control volume method(CV)based on thermodynamic.Based on this method,the inflatable deployment of the folded airbag has been successfully simulated with Abaqus fluid cavity and fluid inflator module.The analysis shows that the inflatable experiment of spindle-shaped airbag is in good agreement with the simulation results,which proves the feasibility and accuracy of the inflation method used in this paper,and according to the pressure curve,the inflation duration of the gasbag can be divided into isobaric expansion and isovolumic expansion.At the same time,the successful simulation of the inflation of various types of airbags shows the universality of the CV method.(3)The inflation of the Tensairity dome is simulated and analyzed,and the timevarying performance of the structure during inflation process is investigated by analyzing the displacement of the shell and the stress of the cable.Considering that the gas temperature that will affect the air pressure in the adiabatic inflatable,three feasible solutions to control the pressure precisely are proposed in this paper,the first solutions which is considered as the optimal one due to the simplest operation and the least amount of calculation.Based on the first solutions,the influence of the construction factors such as the inflating sequence,the scaffold and the type of the support on the structure was discussed respectively.The results show that,for tensairity dome had multiple gasbags,multiple inflatable pumps should be used as much as possible in order to reduce the stress of the structure in the inflating process.In the process of inflating,the upper reticular shell will take the initiative to get rid of the scaffold,so the construction scheme of first removing the scaffold after inflation should be adopted to reduce the construction difficulty.(4)Based on the Abaqus fluid exchange module,the process of gas leakage of the tensairity dome was simulated and analyzed.According to the pressure curve,the gas leakage process can be divided into three stages: rapid descent stage,transitional stage and Smoothing stage.The effects of air leakage area,gas temperature,external load and airbag partitioning on the gas breakage were investigated respectively;it showed that the partitioning of the airbag can control the influence of the air leakage on the structure in the local area.At the same time,the influence of broken cable on the initial state and the load state of the tensairity dome is analyzed,the results show that cable breakage of the tensairity dome does not cause collapse suddenly,structural bearing capacity is the most sensitive to breakage of the lower cable and vertical cable.