Issue 48

Y. Sun et alii, Frattura ed Integrità Strutturale, 48 (2019) 648-665; DOI: 10.3221/IGF-ESIS.48.62 665 [110] Espeso, D.R., Carpio, A., Einarsson, B. (2015). Differential growth of wrinkled biofilms, Phys. Rev. E - Stat. Nonlinear, Soft Matter Phys., 91(2), p. 022710, DOI: 10.1103/PhysRevE.91.022710. [111] Tallinen, T., Chung, J.Y., Rousseau, F., Girard, N., Lefèvre, J., Mahadevan, L. (2016). On the growth and form of cortical convolutions, Nat. Phys., 12 (6), pp. 588-593, DOI: 10.1038/nphys3632. N OMENCLATURE  c Critical wrinkling strain E Young’s modulus, subscripts f and s denote the film and substrate  Poisson’s ratio  Wrinkle wavelength h Film thickness A Wrinkle amplitude  Applied strain  A constant that depends on the mismatch in elastic properties between the film and substrate e Elastic energy in the film per unit surface f G Fracture energy per unit area  t Tensile stress c h Critical fracture thickness L Wrinkle length s Crack spacing N Crack number w Crack width c T Curing time  rr Radial stress   Hoop stress  , r Polar coordinates  Pulling stress of the film at probe tip edge a Radius of probe tip  c Critical wrinkling stress  Indentation depth 1 D Diameter of radial wrinkles 2 D Diameter of circular crack w M Molecular weight p H PS thickness  Substrate viscosity t Time. U Elastic energy  pre Pre-strain n Number of hierarchical transition d Diameter of silicone oil drop