title: Reversible dilatancy in entangled single-wire materials.
abstract: Designing structures that dilate rapidly in both tension and compression would benefit devices such as smart filters, actuators or fasteners. This property however requires an unusual Poisson ratio, or Poisson function at finite strains, which has to vary with applied strain and exceed the familiar bounds: less than 0 in tension and above 1/2 in compression. Here, by combining mechanical tests and discrete element simulations, we show that a simple three-dimensional architected material, made of a self-entangled single long coiled wire, behaves in between discrete and continuum media, with a large and reversible dilatancy in both tension and compression. This unusual behaviour arises from an interplay between the elongation of the coiled wire and rearrangements due to steric effects, which, unlike in traditional discrete media, are hysteretically reversible when the architecture is made of an elastic fibre.
authors.affiliation: Institut Lumière Matière, Université Lyon 1-CNRS, F-69622 Villeurbanne, France.|Université Grenoble Alpes-CNRS, SIMAP, F-38000 Grenoble, France.
authors.forename: David
authors.initials: D
authors.lastname: Rodney
authors.affiliation: Université Grenoble Alpes-CNRS, SIMAP, F-38000 Grenoble, France.|Université Grenoble Alpes-CNRS, 3SR Lab, F-38000 Grenoble, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gadot
authors.affiliation: Université Grenoble Alpes-CNRS, 3SR Lab, F-38000 Grenoble, France.
authors.forename: Oriol Riu
authors.initials: OR
authors.lastname: Martinez
authors.affiliation: Université Grenoble Alpes-CNRS, 3SR Lab, F-38000 Grenoble, France.
authors.forename: Sabine Rolland
authors.initials: SR
authors.lastname: du Roscoat
authors.affiliation: Université Grenoble Alpes-CNRS, 3SR Lab, F-38000 Grenoble, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Orgéas
mesh_terms: D001672:Biocompatible Materials; D003300:Copper / Q000737:chemistry*; D008422:Materials Testing; D019563:Mechanics; D009532:Nickel / Q000737:chemistry*; D009757:Nylons / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D009757:Nylons; C040654:titanium nickelide; D003300:Copper; D009532:Nickel; D014025:Titanium