Abstract :
Wool, bird nests, or coton are multiscale materials made of simple elements, fibers, coupled through disorder and frictionnal interaction. These complex interactions lead to a new mechanical response with emerging properties, such as palsticity and non linear
reponses. Using experiments on model systems and simulation, I will explore the mechanical response of such an assembly to an uniaxial compression, and try to link the observed scalings to the micro scale structure of the fiber network.
In a second part, I will explore the unfolding of poplar tree fruits. These fruits, while quite small (5mm), can release a coton ball of several cm that plays a important role in the transport of the seeds. Looking at the different scales of the fruits, I will
isolate the key ingredients allowing to unpack fibers assemblies, and try to reproduce it in the lab using active fibers.
