Study and development of concepts of auxetic structures in bio-inspired design

This work discusses the experience of using auxetic (negative Poisson's ratio) materials in different design objects, including chairs, bags, seat belts, etc., developed by the authors with their students. Auxetics have become of interest in engineering, whenever a support instead of a pronounced flexure, of a cellular, therefore lightweight material, is desirable. Structures have been calculated and modelled as chiral with defined geometrical parameters and then applied to concepts with the fabrication of real models using neoprene or generally rubbery material. Indications on the possible sensations of the user are suggested, which provided rationale for likely improved comfort and/or desirability of contact. Limitations of this study in terms of material experience appear the use of a single material as for auxetic properties and the focusing on one single possible auxetic structure, the chiral one. Despite this, this could be considered as a starting point for a possible database of material experience on the use of auxetics. From these considerations, it appears as the use of auxetic structures would lead to a more sustainable scenario for these objects, especially because improved user's experience would extend their duration of life and lead to a lower rate of discarded pieces.