Comprehensive study of the off-axis mechanical behaviors of a Polytetrafluoroethylene‐ coated fabric after 23 Years of service at Shanghai stadium

Coated fabrics can experience mechanical performance degradation due to environmental factors and long-term stress during service. Hence, studying the mechanical behaviors of these materials after aging is crucial. While PTFE (polytetrafluoroethylene)-coated fabrics are more commonly used than PVC (polyvinyl chloride)-coated fabrics, limited research exists on their performance after aging in practical engineering applications. PTFE-coated fabrics are primarily used in large-span fabric structures, where their mechanical performance under tensile-shear stress is crucial. This study aims to investigate the mechanical behaviors of PTFE-coated fabrics after practical aging under tension-shear stress. Test materials included decommissioned Saint-Gobain Sheerfill-II PTFE-coated fabrics, which had served for 23 years at Shanghai Stadium, and identical new fabrics. Monotonic tensile, central tearing, and cyclic tensile tests were conducted at seven different off-axis angles to compare the mechanical properties of aged fabrics with new fabrics, including tensile strength, tearing strength, modulus of elasticity, and ratcheting strain. Additionally, this study explored changes in failure mechanisms, tearing mechanisms, applicability of strength criteria, and suitability of the orthotropic model after aging. This provides a comprehensive understanding of the mechanical behaviors of aged PTFE-coated fabrics and valuable insights for engineering design.