Modelling the Constitutive Behaviour of Recycled PET for the Manufacture of Woven Fabrics

Recycling polyethylene terephthalate (rPET) from packaging materials consumes a vast amount of energy and incurs significant economic and environmental costs. This study proposes directly recycling rPET into woven fabrics to eliminate reprocessing while still preserving the mechanical performance of the material. The mechanical properties of rPET were tested along two orthogonal directions, and the resulting test data were used to calibrate an elasto-plastic model in order to capture the constitutive behaviour of the material. Additionally, the virtual weaving of rPET fibres into fabrics was modelled using finite element analysis (FEA) to replicate the actual manufacturing process. The results show that rPET that is directly recycled into woven fabrics exhibits superior performance to the same material derived from reprocessing. A strong anisotropy of rPET materials was observed, with distinct elastic and ductile behaviours. The FEA simulation also revealed the critical role of the ductility of rPET fibres when used as warp yarns. The process parameters to achieve a successful weaving operation for different yarn configurations, taking into account the motion and tension of the fibres during manufacture, were also identified. A further sensitivity study highlights the influence of friction between the fibres on the tension force of warp yarns. The virtual manufacture-by-weaving model suggests that utilising rPET with a simplified recycling approach can lead to the sustainable manufacture of fabrics with broad industrial applications.