A modified material model describing the load-deflection behavior of air-supported fabric structure with decreasing stress

Air-supported fabric structures are often used as formwork for constructing concrete shells. However, the load-deflection responses of these quick deployment structures are difficult to be simulated by current material models because the decreasing stress can cause the change of the elasticity. In this study, a new modified material model is developed which can improve the ability of accurately predicting the dynamic behaviors of air-supported fabric structures under vertical load. Uniaxial and biaxial tensile tests are performed to understand the mechanical property of the fabrics, which is used to construct the modified material model. Two parameters are used and adjusted to describe the changing characteristics of the orthotropic elastic moduli. This modified material model is then incorporated in to the finite element simulation software, which is then compared with a vertical loading experiment on a large-scale fabric structure. The cycle of loading/unloading curves of biaxial tensile tests demonstrates that elastic moduli do decrease with the stress during unloading procedure. Compared with the vertical loading experiment, the modified material model can significantly increase the accuracy in contrast with three conventionally-used material models. This modified material model is expected suitable for predicting and analyzing the responses of PVC-coated polyester fabric structures especially dealing with the decreasing stress in fabrics.