The failure of granular systems under large loads, whether dry or in a surrounding medium, involves many complex processes including the buildup of frictional contacts, granular flow, and fracture. In the presence of a surrounding matrix, such as a viscoelastic binder, even more mechanisms come into play. In this talk, we will discuss methods to simulate these systems using a bonded particle approach recently implemented in LAMMPS, a massively parallel open source particle dynamics simulator. In a bonded particle model, matter is represented by discrete particles connected by a network of breakable springs with varying properties to represent different materials. We will describe the application of such models to study failure of both dry granular packings and granular packings within a viscoelastic binder. During loading, we monitor the evolution of macroscopic stresses and porosity and track the nucleation and the failure of individual grains. By varying the loading geometry, we study how material properties and strain rate affect the yield surface and discuss how such results can be extended to inform continuum level modeling and generate digital twins of manufactured components.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA-0003525.