Strain and stress at the fracture of percolative media

We measured the strain and the stress of a perforated metal foil and of a diluted elastic network near the percolation threshold. We used two different techniques: in the first, the strain is increased continuously and monotonically until the system ruptures, whereas in the second, it is the stress which is increased monotonically. We determined the critical exponent of the fracture stress σ f ∼(p c −p)τ f , with T f =2.5±0,4 and the critical exponent of the fracture strain e f ∼(p c −p) −Tu with T u =1.4±0.2. A theoretical interpretation of the results is proposed within the framework of the nodes-links-blobs picture Determination au voisinage du seuil de percolation de la deformation et de la contrainte d'une feuille de metal perforee et d'un reseau elastique dilue, par augmentation reguliere de la deformation d'une part et de la contrainte d'autre part. Determination de l'exposant critique de la contrainte a la rupture et de la deformation a la rupture. Interpretation theorique des resultats