Biaxial Tensile Testing of Knitted Fabrics Exploring Natural Fibre Properties in Membrane Architecture

Abstract

The increasing concern over the use of non‐renewable and energy‐intensive polymers is leading to a revaluation of resources and fabrication methods in architectural textiles, where traditional woven membranes and foils are used in tensile structure applications. CNC‐knitting is emerging as a promising technology that enables the use of a wider range of fibres, including stiffer natural fibres, with customisation of membrane patterns and shapes. The determination of elastic properties is necessary to design with knitted membranes, yet it remains challenging because biaxial testing standards in the construction sector are tuned for woven fabrics. This study investigates the mechanics of knitted textiles through a systematic biaxial testing campaign focusing on the influence of yarn material, two natural fibres, hemp and flax, in comparison with one synthetic fibre. Challenges in testing and findings on the characterisation of the load–elongation behaviour, along with the determination of elastic properties for each material–structure combination, are presented as relevant preliminary results which can support designers in material selection, inform simulation workflows, and enable feasibility assessments in design applications.