Statistical characteristics of naturally aged PVDF-coated fabrics’ mechanical properties and structural reliability index

Abstract

Membrane structures deteriorate with time. This results in reduction of their resistance, and consequently, of their reliability. Material aging is one of the main causes of structure deterioration. This paper investigates statistical characteristics of naturally aged polyvinylidene fluoride PVDF-coated fabrics' mechanical properties and calculates reliability indexes on the basis of Central Point Method and Rackwitz-Fiessler Method. Five groups of experimental fabrics were taken from different existing engineering structures or indoor warehouse in China, which have been naturally aged for more than 10 years. First, series of tearing tests, uniaxial and biaxial tensile tests were carried out to study the mechanical properties. Then, the uncertainties of material properties, material's dimension, computational model and load effects were discussed and the reliability indexes were studied by two methods according to the ultimate limit state. Finally, reliability indexes of aged PVDF-coated fabrics were compared with that of unaged coated fabrics. Results show that the impact of natural ageing on the properties of PVDF-coated fabric can not be ignored in reliability analysis and membrane structures design. These data offer a further understanding of aged PVDF-coated fabrics' mechanical properties and provide references for the durability analysis of tensioned membrane structures.