Bending and Wrinkling as Competing Relaxation Pathways of Strained Free-Hanging Films
An equilibrium phase diagram for the shape of compressively strained free-hanging films is developed by minimizing the total strain energy. For small strain gradients , the film wrinkles, while for sufficiently large , a phase transition from wrinkling to bending occurs. The average strain in the bilayer film is denoted . Thickness, Poisson's ratio, and the Young modulus for the first and second layers are denoted by , , and , , . The equilibrium radius of rolled-up tube is represented by and the wavelength of wrinkles by .
 P. Cendula, S. Kiravittaya, Y. F. Mei, Ch. Deneke, and O. G. Schmidt, "Bending and Wrinkling as Competing Relaxation Pathways for Strained Free-Hanging Films," Physical Review B, 79(8), 2009 p. 085429. doi:10.1103/PhysRevB.79.085429.
Additional information can be obtained from the author at cendos (at) gmail (dot) com.