Speaker
Description
Many structures around us achieve mechanical stability against their
own weight through friction. Examples include arch bridges,
house-of-cards construction, and sandpile stabilized by their angle
of repose. In these systems, friction and geometry work together
to suppress sliding and enables mechanical equilibrium. But what
(if any) mechanism contributes to the strength of such
friction-stabilized configurations?
In this talk, we investigate a minimal model consisting of three
cylindrical particles stacked via side-to-side contact under gravity,
forming a triangular arrangement. A quasi-static compressive
force is applied from above via a wall. As the force increases,
the structure eventually collapses due to sliding at the contact
with the floor. We define the threshold force required to induce
this failure as the yield force, and study its dependence on the
floor friction coefficient and the stiffness of the cylinders.
Surprisingly, in the rigid-body case (i.e., no deformation), we find
a sharp transition: the yield force diverges at a critical friction
coefficient \mu_c ~ 0.268. To investigate more realistic conditions,
we employ the discrete element method (DEM) to analyze a pile
of elastic cylinders. We numerically observe a singular behavior
as the dimensionless effective elastic modulus becomes large.
Furthermore, we derive a unified scaling function to describe
this singularity.
