Exprimental Technology For Tri-tension Of Fabric Joint And Bi-extension Of Fabric And Exprimental Study

As the main material of architecture membrane structure, the mechanical properties of architectural fabric play important roles on structural analysis, engineering design, manufacture and construction procedure. So it is particularly important to grasp the mechanical properties of the fabric. The flexible connectors of membrane structure are the weak parts for the structure, but there is little research of the flexible mechanical performance at home and abroad. So it is necessary to conduct an exploration in this field. In this paper, the architectural fabric and fabric joint were chosen to be the object, which was investigated through theoretical, experimental and numerical analysis methods to recongnize their mechanical performance.First of all, the differences between constant tension-rate test and constant rate tests were compared thoroughly, then the constant tension-rate test and constant rate tests of PVC fabric were carried out respectively, and the stress-strain curves were obtained. Then the elastic modulus and Poisson’s ratio were calculated based on the orthotropic theory of plane composites. The differences of elastic engineering constants calculated by different formulas were compared.Secondly, according to the characteristics of the biaxial shear deformation of fabric, the calculation formulas of engineering shear strain and shear stress were formulated, then the scheme of biaxial shear test were given. The biaxial shear tests of the PVC and PTFE fabric were carried out respectively, and the shear stress-strain curves and shear modulus were obtained. Then the differences of shear modulus calculated by different formulas were compared.Thirdly, the development of three-dimensional tensile tester was introduced. The three-dimensional tensile tester includes the horizontal biaxial tensile tester and z-axial tensile tester. The z-axial tensile tester bench contains the fixed part and the movable mechanism.Finally, the loading protocol and the test scheme of three-dimensional tensile tests were presented. Nine kinds of three-dimensional tensile tests were carried out. The horizontal biaxial tension curves and z-axial tension curves were obtained. The differences between the vertical tensile test and the off-axis tensile test were compared. Based on the simplified constitutive model of fabric, the numerical simulations of the vertical tensile test of 3D fabric joint were carried out.