Politecnico di Torino - Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

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Auxetic patternChignonMeta-material


The invention consists in applying an auxetic pattern to a design object, discretizing the meta-material on a spherical geometry for a widespread use in fashion accessories. In particular for the realization of accessories for hairstyles, such as for the hair bun net that have properties that can be worn in a simple way, maintaining the shape and also creating an interesting design.

Technical features

The algorithm that governs the design of the chignon network starts from a pattern with a triangular base grid. The cell is composed of three arches mirroring their opposites. The concavity factor of the arc is given by the displacement of the three middle points of the sides that make up the perimeter, thus defining the auxetic factor. The cell is then concatenated to the following one, thus continuing until the complete frame is defined. Near the side of the sphere there is the hole for the entrance of the bun that has a shape that follows the pattern. At the hole the material is thicker. The material chosen is a silicone compound with a resistance of about 30 shore that allows to obtain a good resistance combined with a high elasticity (500 stretching factor).

Possible Applications

  • Fashion hairstyles;
  • Sports hairstyles.


  • Computational design that allows to draw simulating mechanical performance together with the shape;
  • Higer mechanical resistance;
  • Water resistance.