Expérimental et théorique
Thin elastic sheets or wires easily fold when deposited on substrates. The relaxation of these folds or wrinkles depend on the ability of the sheet to slide on the substrate, while the elastic energy stored in the folds or wrinkles promotes the relaxation of the shape. Hence, such problems interestingly couple elasticity to frictional and sliding behaviors in thin elastic sheets. The internship aims at exploring several aspects : How does the interplay between film deformation and friction affect the development of buckling instabilities and fold trapping? What is the contribution of film roughness and polymer viscoelasticity? To answer to these questions, we will carry out experiments in which a viscoelastic polymer strip is laid at imposed vertical velocity on a glass plate while the development of buckling instabilities and friction at the rough contact area at the glass/strip interface are continuously monitored. Based on these observations, we will seek to develop a physical description of the role of friction in the formation and trapping of wrinkles in relation to the mechanical and roughness properties of the polymer film.