Interactions of slender elastic structures with complex media like granular materials

Slender elastic structures are extremely flexible and get easily unstable. As a consequence of their high geometrical aspect ratio, slender structures can be sensitive to low forces of various origins and exhibit complex mechanical behaviors due to the associated couplings with the surrounding medium, whatever it is (fluid, elastic medium, gels, frictional substrate, granular material…).
The effect of flexibility has recently motivated a growing number of studies. This is in particular the case of the elasto-capillary problems (interaction between slender structures and capillary forces), and of the fluid-structure interaction, where water or air flows induce shape reconfiguration and streamlining of elastic structure, leading to drag reduction.
Here we will review various cases of interaction of elastic structures with complex external medium, focusing on granular medium. Direct applications of this problem will be chosen in the bio-physics domain, like the growth of plant roots in structured soils.