elasto-capillary effects of a soaked membrane
This is the main subject of my PhD thesis. The study is inspired by the work of P. Grandgeorge et al.
We build a 2D model of this soaked, porous membrane, it deforms under end displacement control. The liquid serves as a geometry constraint : the liquid-air interfaces confine the membrane to large deformations in the vertical direction, thus the membrane forms wrinkles to meet geometry conditions. The precise behavior of the system depends on the elasto-capillary length, the length of the membrane and the volume of the liquid.
Here is a video showing one of our solutions, note that x and y axis are not equally scaled.
We can see that a concentration gradually appears from the initially homogeneous wrinkles. In fact, the experimental observation found something similar, and we further explain the phenomenon with a more analytical model.