Abstract: To define the biaxial tensile properties of fabric membrane material within the full-stress range,the biaxial monotonic tensile experiments of typical PVDF coated fabric were conducted by setting seven loading ratios. A developed MATLAB program was used to achieve complex deformation properties and accurate elastic parameters of the coated fabric. By this program, the response surface analysis of deformation and mechanical parameters were carried out to reveal the variation and evolution in elasticity modulus, Poisson’s ratio, and orthotropy of the coated fabric under different stress levels and ratios. The results show that elastic parameters and orthotropic characteristics of the material vary noteworthily with stress ratios and levels within the full-stress range. In addition, coupled stiffness coefficient was introduced to represent the proportion of elongation and shrinkage in biaxial monotonic tensile test. The formula of elasticity modulus was derived based on the uniaxial and biaxial tensile stress-strain relation, and the obtained values were in good agreement with the experiment values. The conclusions of investigation could offer beneficial reference for tensile mechanical property of coated fabrics and membrane failure analysis in membrane structure engineering.

Key words: plain woven fabrics, response surface, biaxial monotonic tensile, elastic parameters, full-stress range, composites