Our everyday experience of tearing (fracture in thin sheets) can be frustrating (not-so-"easy opening" packages, removing adhesive tape…). In fact tearing paths are very reproducible and i will show that they obey simple laws, with consequences in engineering at many scales, including in many examples around us.
I will review several tearing problems, where experimental fracture path are very robust. I will show how a simplistic (geometric) framework, based on energy arguments, provides very insightful information.
However a complete description should include additional effects, and in particular anisotropy, a consequence of the manufacturing of thin sheets; tearing a piece a paper brings us to deep questions in fracture mechanics.
Here is a picture:
Un café sera servi à 11H dans le Hall