Tensile behavior of PVC-coated woven membrane materials under uni- and bi-axial loads

Tensile characteristics are the most significant mechanical properties for coated woven fabrics as membrane materials used in lightweight constructions. Factors that might affect test results of the material under uni- and biaxial tensile loads are examined. After series of tensile tests on PVC-coated membrane materials, it is demonstrated that (1) to measure the strains in the two perpendicular directions, the contact method by the needle extensometer does not interfere the correct data recording; (2) the positions where the strains are measured on specimens have a great influence on the test results of the stiffness and Poisson's ratio in warp direction under uni-axial load; (3) to perform bi-axial tensile tests the size of the cruciform specimen in bi-axial tensile test can be much smaller than those suggested in the literature. The tensile behavior of coated membrane materials under biaxial loads are affected dramatically by the stress ratio in the warp and fill directions. Besides the residual strains of coated membrane materials are affected not only by the properties of the constituent yams and woven structure but also by loading conditions during the coating process. (c) 2007 Wiley Periodicals, Inc.