3D-Printed Auxetic Structures with Textile Integrations

Additively manufactured auxetic metamaterials presents new opportunities for the development of functional and adaptive material systems. Using a mixed methodology with a quantitative approach, this study investigates the application of fused deposition modeling (FDM) to produce auxetic structures with textile integrations. Auxetic materials are characterised by their negative Poisson’s ratio (PR) and offer unique mechanical properties such as enhanced energy absorption and adaptive stiffness. This makes them highly relevant to personal protective equipment (PPE) and other fields. The mechanical parameters PR, adhesive forces and deformation behaviour were experimentally measured using a factorial approach. It was concluded that the textile integration decreased the PR of the aux-etic structures where a significant difference was found between textile integration with no textile, and the textile porosities. Furthermore, a strain-rate depend-ant auxetic property where a switch from a negative to a positive PR was detected in the small porosity samples, leading to the indication that textiles could be used for tunability of the PR. The effect of the textile porosity on the adhesive forces were tested where the smaller porosity presented superior adhesive forces, but the textiles cohesive forces were weaker and needed to be considered. As for the de-formation behaviour, very low cyclic compression tests were performed where the deformation at maximum load (DML) and the residual deformations (RD) were tested. Both DML and the RD showed that textile integration decreased the amount of deformation but also the rates. Due to the novelty of this study, further research is required to fully understand how the textile integration affects auxetic structures, but these findings conclude that hybrid systems could be used for improved mechanical functionality of auxetics.