Mechanical Properties Of Coated Fabric And Its Effect On Structure

Membrane structure is a new space structure system after the grid structure,suspended-cable structure and thin shell structure.Since the origin of modern membrane structure in the mid-20 th century,membrane structure has entered a rapid development period,and modern membrane structure has been applied in architecture on a large scale.As the most widely used materials in membrane structure,the mechanical properties of coated fabrics are closely related to the engineering design,analysis and calculation of membrane structures.In this paper,a series of experiments have been taken on Ferrari1202S2 material,including uniaxial tensile test,uniaxial cyclic tensile test,biaxial tensile test,biaxial shear test and trapezoidal tear test.The mechanical properties of membrane materials are studied by means of constitutive analysis and numerical simulation.Firstly,the uniaxial tensile strength test has been taken to obtain the ultimate tensile strength of the material,which provided the maximum stress level for the biaxial tensile test.Then,through a series of uniaxial cyclic tensile tests and biaxial tensile tests,a uniaxial cyclic tensile material model,a biaxial linear material model and a biaxial nonlinear material model have been established respectively,and the elastic modulus and poisson’s ratio of the Ferrari1202S2 material under the three material models can be obtained.The elastic modulus obtained by uniaxial cyclic tensile material model and biaxial linear material model is constant,while the biaxial nonlinear material model establishes a functional relation between stress ratio and elastic modulus.Secondly,biaxial shear test has been carried out considering the influence of shear stress level on shear modulus of membrane materials,and the loading method of biaxial shear test has been introduced.The shear stress-shear strain curve of membrane materials under different shear stress levels can be obtained,and the shear modulus of membrane materials can be obtained according to the existing calculation formula.Thirdly,a series of trapezoidal tear tests have been carried out considering the effects of slit length,clamping angle and loading rate on the tear performance of membrane materials.The test method and results of trapezoidal tear test are mainly introduced,and the tear mechanism of membrane materials and the influencing factors of tear strength are analyzed.Finally,in order to understand the influence of elastic modulus,poisson’s ratio and shear modulus on structural deformation accurately,finite element analysis has been carried out on an inflatable membrane structure and a roof structure model of a stadium by changing the mechanical parameters of the membrane material.The numerical simulation results show that the elastic modulus and shear modulus of the membrane have significant effects on the deformation of the membrane structure.It is suggested that a more practical constitutive model considering the stress level in the membrane should be established to improve the accuracy of analysis and calculation.