Buckling and post-buckling of stressed straight-sided wrinkles: experimental AFM observations of bubbles formation and finite element simulations

The transition from a straight-sided wrinkle to a periodic distribution of bubbles has been experimentally studied by atomic force microscopy for a stressed thin film relying on a substrate. A non-linear numerical analysis has been carried out and the different steps of the wrinkle evolution have been characterized. Different parameters of the buckling structure such as the shape parameter of the blisters and the stress relaxation have been determined and compared to the experimental data. The comparison of elastic strain energies has highlighted the possible coexistence of structures with different wavelengths. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.