Study And Applications On Mechanical Properties Of Membrane Materials And Structures

In the 50 years since its birth, membrane structure has become one of the mostimportant structures in the field of large span space structures. It is famous for thevariable architectural styles and the light and floating structural properties. Membranestructure differs greatly from the traditional structures in both material property andstructural performance. However, the research in this area at home still lags behind,which severely restricts the development of the domestic membrane industry andmembrane structures.Systematic research is conducted on the mechanical performance of membranematerials and membrane structures, especially the coated fabric membranes. Theresearch involves the basic mechanical properties, strength indexes and mechanicalconstants of membrane materials; the behavior of connection between membraneunits; and the measurement technique of membrane tension. Engineering test andanalysis is adopted as the main research method.The constitution, the classification and the physical performance of membranematerials are expounded in this dissertation. Through test, an analysis is made of thefour basic mechanical properties of membrane materials including the nonlinearity,the nonelasticity, the orthotropy and the viscoelasticity.The tensile strength and the tear strength of membrane materials are studied by testmethod. By comparison between the test results of different test methods, areasonable test method is proposed to determine the strength indexes of membranematerials. A great amount of strength indexes test data of membrane materials isaccumulated. And these strength indexes test data is verified to obey normaldistribution by the skewness-kurtosis testing method. Furthermore, the strengthindexes of several kinds of coated fabrics which are often used in structures aredetermined.New test instruments are devised to determine the mechanical performance ofmembrane materials, including the biaxial tension machine and the in-plane shear tester. According to the FEA results, also referring to the advanced methods in theworld, the methods to test the elastic constants of membrane materials are determined,the cross-shaped biaxial proportional tension method for membrane elastic modulusand the in-plane shear test method for membrane shear modulus. Thereafter, themechanical constants and constitutive relationships of several common coated fabricsare tested and established.The damage patterns of several kinds of connection, the sealing and gluingmembrane-membrane joints and plate clamping and U-shape clampingmembrane-riNd edge joints, are analyzed. And the force transmission mechanisms fordifferent connection modes are clarified. Orthogonal combination test are designedand conducted to explore the influence of different parameters on the performance ofjoints. Furthermore, reasonable connecting parameters and connecting strength fordifferent joints are given based on the test results.Finally, on the basis of previous achievements of our research group, the measuringdevice for membrane tension is improved and applied to several kinds of membranestructure projects to assess the pulling construction quality.Test machines devised and test methods concluded and validated by tests constitutethe main body of the Shanghai local code Technical Specification for Inspection ofMembrane Structures. The research results on the mechanical performance ofmembrane materials and membrane structures can provide technical support for thecomputation, design, construction and safety evaluation of membrane structures.