Study on Deformation Performance of PVC Membrane Materials under Biaxial Cyclic Tensile Loads

Abstract

This article presents the mechanical properties of PVC coated fabrics under biaxial cyclic tensile loads. Tests of PVC at five load ratios in the warp and weft directions, which are 0:1, 1:2, 1:1, 2:1 and 1:0 respectively, were carried out, and tensile performances of the samples under biaxial tensile loads were analyzed. The test results show that the PVC membrane is highly nonlinear and orthotropic under biaxial tensile loads. With the increase of loading cycles, the total residual strain is nearly unchangeable and the hysteresis curve becomes stable. Slope of warp curve is larger than weft curves, and the weft loop area is greater than the warp one with the same load ratio. The generalized poisson ratio changes due to variations of the load ratio (R). when R<1, the experimental values and theoretical values of the generalized poisson's ratio are negative. When R≥1, generalized poisson's ratios tend to be constant, When the load ratio are 0:1 and 1:0, the curves become straight lines.