Study On Pretension And Deformation Characteristics Of Planar Skeleton Membrane Structure

The membrane structure is a flexible structure,and it is necessary to have proper pre-tension to support the beautiful shape,so the pre-tension is the core and key to ensure in the whole process of design and construction.At the same time,due to the nature of the membrane itself,the pre-tension is greatly affected by the environment,and many environmental factors must be considered when selecting the pre-tension.In this paper,the planar skeleton membrane structure in the architectural membrane structure is taken as an example.The PTFE membrane is selected,and the rectangular and triangular elements are used to carry out the theoretical and simulation studies on the pre-tension and deformation characteristics respectively,and a reasonable tensioning scheme and tensioning device were designed to carry out the pretension creep test.Specifically,the main work of the thesis is as follows:(1)Analysis of the value of pre-tensionRegarding the choice of pre-tension,this paper analyzes the value of the pretension of the membrane structure by ANSYS software according to the installation conditions and the relevant requirements in the Technical Specification for Membrane Structures,and finds the range of pre-tension of two forms of membrane structure.Then,the stress and deformation of the membrane structure are analyzed under different pretensions.(2)Effect of temperature on pre-tension and deformation characteristics of membrane structureTemperature not only has thermal expansion effect on the membrane,but also changes the elastic modulus of the membrane.In this paper,ANSYS software is used to simulate the pre-tension of membrane structure at different temperatures,and the relationship between pre-tension and temperature change of two forms of membrane structure is obtained.Under the uniform load,the influence of different temperature on the deformation of the membrane surface,the law of pre-tension and membrane surface deformation with temperature was found out.A method for selecting the pre-tension was summarized,which provided some references for the design and installation of the membrane structure.(3)Effect of creep on pre-tension and deformation characteristics of membrane structureBased on the theoretical formula of creep mechanics,the appropriate creep constitutive model is selected for the membrane structure.The creep is studied from the two aspects--pre-tension and membrane deformation.The theoretical formula of planar membrane structure is based on Euler method and ANSYS is used to find out the variation law of pre-tension and membrane surface deformation of two forms of membrane structure under creep,which has certain reference significance for the design and installation of planar membrane structure.(4)Pre-tension engineering test of membrane structural unitOn the basis of the existing membrane unit tensioning device,through a comparative analysis,a new type of tensioning device was improved,and a tensioning scheme was designed.After the membrane tension is completed,the membrane unit is subjected to a pre-tension creep test.The reliability of the simulation results was verified by comparison of experimental and simulation data.