Abstract

We have recently developed a new method for simulating deformable particles like cells, emulsions, foams, and elastoplastic particles.  It is a general framework that allows for many aspects of hybrid FEM /DEM simulations but with significant simplifications and speedup.  It also extends earlier models like surface evolver, vertex models, and voronoi based models to allow for more shape degrees of freedom and applies to systems with a wide range of densities from single particles to confluent cell packings. We use this new model to study mechanically stable packings of deformable and rigid particles. We present the densities and average contact numbers for collections of jammed mono- and bi-disperse packings of circulo-polygons for a range of shape factors, edge numbers, and system sizes. For rigid particles, we find mechanically stable packings with fewer than isostatic contacts.  For deformable polygons, we identify a new phase transition between non-confluent and confluent systems that occurs when the particle shape factor is comparable to the average shape factor for Voronoi polygons of disk packings.