Entanglement in filamentous networks

Packings of high aspect ratio filaments can form an effectively cohesive structure by virtue of entanglements driven by frictional and steric effects - e.g. a bird's nest. But how can we define and quantify entanglement and its role in such systems? To address this, we experimentally probe the jammed state of straight elastic rods using a combination of imaging and mechanical testing. Micro-CT scans allows us to observe the configurations in a tangled rod network with each filament resolved by image processing, and quantify their entanglement at a mesoscopic scale. This allows us to couple the geometry and topology of entanglement with the mechanical behavior of a randomly packed set of rods.