Compressing and Fracturing 2D Crystals

In this project we simulate a two dimensional aggregate of slightly adhesive droplets in a viscous environment while compressed between two parallel walls, of which only one moves, mimicking the experiment of Ono-dit-Biot et al. [Soft Matter 17, 1194-1201 (2021)]. For highly monodisperse samples, we observe the structure undergo a transition in a single catastrophic fracture event. As the wall moves, the sample, arranged like a hexagonal closed packed crystal, rearranges itself via row reduction, and gaining one column. As the speed of the walls increases, viscous effects become more relevant. This results in the force necessary for a fracture to become/be higher, alongside the appearance of defects in the crystals during/by the fracture. On the other hand, increasing polydispersity, towards a glassier aggregate, leads to a breakage in smaller, more localized fractures, where catastrophic global fractures events, no longer occur.