Study On Simplified Coupling Analysis Method Of Closed Tensioned Membrane Structure

Membrane structures are widely used in railway stations,stadiums and other large span structures.Compared with reinforced concrete structures,the light weight and flexibility of membrane structures make them susceptible to large vibrations and deformations in the flow field,which in turn affects the flow field state and changes the pressure on the membrane surface,producing a fluid-structure coupling effect between the membrane and the flow field.The current methods to study the fluid-structure coupling effect are air-bomb model wind tunnel test,numerical simulation and simplified coupling analysis.The air-bomb model wind tunnel test is more difficult to apply due to the limitation of similar criterion and measurement technology;the numerical simulation depends on the high performance computing platform,which is huge for large structures;the simplified coupling analysis method can avoid the above problems,but its analysis accuracy still needs to be studied.In this paper,simplified coupled modal analysis and dynamic analysis of closed tension membrane structures are carried out based on Laplace equation,thin-wing theory,two-dimensional aerodynamic acoustic pressure theory and three-dimensional aerodynamic acoustic pressure theory,and the applicability and accuracy of each simplified coupled analysis method are studied by comparing with the results of fluid-solid coupling analysis.The main research contents are as follows.(1)A finite element model of the closed tension membrane structure was established using potential flow theory.The accuracy of each simplified coupling analysis method was investigated through simplified coupling modal analysis and fluid-solid coupling modal analysis when the membrane thickness,membrane surface pre-stress,size and vector-span ratio were varied.The simplified coupling analysis method based on threedimensional aerodynamic acoustic pressure theory is more accurate in the modal analysis because the change of air density in the transmission process of acoustic waves is considered.(2)The effects of additional mass and aerodynamic damping on the dynamic response of the membrane surface of the simplified coupling method were investigated in the stationary flow field based on the Laplace equation.The accuracy of each simplified coupling analysis method and the variation of accuracy with structural parameters are studied by simplified coupling dynamic analysis and fluid-structure coupling dynamic analysis when the thickness of membrane surface,membrane surface pre-stress and vector-span ratio are varied.In the stationary flow field,both the additional mass and the aerodynamic damping have obvious effects on the dynamic response of the membrane surface.The deviation of the dynamic response of each simplified coupling method is smaller in the region where the influence of aerodynamic damping on the membrane surface is large.(3)Different simplified coupling methods are used to analyze the dynamic response of the closed tensioned membrane structure in the wind velocity,turbulence and frequency of the incoming flow,and the results are compared with those of the fluid-solid coupling analysis.In the wind field,the incoming flow characteristics have a great influence on the accuracy of each simplified coupling analysis method.(4)The additional mass and aerodynamic damping generated by the turbulent pulsation volume are calculated by Reynolds stress under the action of turbulence,and the application of the simplified coupling analysis methods in turbulent fields is explored based on the Laplace equation.It is effective to consider the additional mass and aerodynamic damping generated by turbulent pulsations through Reynolds stresses when performing simplified coupled dynamic analysis of structures in turbulent flows.The study in this paper contributes to the understanding of the reliability of the simplified coupled analysis method.It can provide a reference for the design of simplified analysis of fluid-structure coupling of membrane structures.