Modeling Compaction of Granular Composites Consisting of Brittle Powder and Polymer Binder

Stefan Povolny, Michael A Homel

Keywords: material point method, granular composite, compaction, mesoscale modeling

TL;DR: We model hot-pressing of a granular composite to understand how composition, structure, and processing affect the mechanical properties of the pressed part.

Abstract: Many materials are manufactured via the hot compaction of a granular material consisting of composite grains made of brittle powder and polymer binder. We seek to understand what processes affect the strength of the final compacted part given a target density. To that end, we use the Material Point Method (MPM) to numerically study the dependence of final part strength on the mesoscale characteristics of the powder including relative properties of the constituent phases, the spatial distribution of the phases within a grain, and potential surface effects. Much of the effort has gone towards developing algorithmic tools for simulating the powder compaction process followed by a numerical strength test. These include time-dependent moving boundary conditions, numerical healing/annealing, and temperature-dependent material properties. These techniques, as well as some analysis results, will be presented. Initial results suggest minor sensitivity of the part strength to variations in polymer binder strength.