Multiphysics Simulations of Rigid and Deformable Discrete Bodies

The newest version of the Particle Flow Code, PFC 5.0, is used to explore self-assembly of complex shaped, rigid particles with embedded magnets and the mechanical properties of large assemblies of carbon nanotubes. PFC 5.0 is a computational platform that allows for rapid simulations of particulate systems via the Distinct Element Method. For the self-assembly investigation, complex-shaped particles described as triangulated surfaces are approximated by rigidly connected spheres. An algorithm approximating the particle mid-surface is used to determine the sphere distribution. Custom interactions laws are created either with a scripting language or with compiled dll's. In this case, a custom dll is described that simulates both the mechanical and magnetic interactions between particles. Simulations using this linear-dipole interaction law produce realistic responses for simplified geometries and when applied to the complex geometry of the self-assembly problem. PFC aptly handles both intimate and long-range interactions effectively. For the carbon nanotube investigation, strings of particles are bonded with a custom interaction law to simulate elastic beams. A unique van der Waals interaction law has been developed to alleviate the commonly used corrugated potential. The results demonstrate a strong agreement between laboratory experiments and simulations of macro-sized samples of carbon nanotube assemblies.