Post-wrinkling analysis of a torsionally sheared annular thin film by using a compound series method

This paper investigates the torsional wrinkling behavior of an annular thin film. Non-dimensional nonlinear von Karman buckling equations are established, which are solved by introducing a compound series method to acquire the post-wrinkling characteristics. The proposed theoretical model can accurately predict the critical wrinkling behavior and post-wrinkling characteristics of the annular thin film, which are verified by the experimental measurement based on the digital image correlation (DIC) technique. The theoretical results show that the post-wrinkling stress is intimately associated with the wrinkle configuration in the post-wrinkling stage. The hoop post-wrinkling stress along the wrinkle texture direction of the annular thin film dictates the wrinkle evolution. The wrinkle number remains constant in the elastic regime, which is determined by the critical buckling load factor. The results provide good guides to tune or control the wrinkles in the thin film.