(442z) Finite Element Simulations of Granular Compaction Part 1: Roller Compaction

Finite
Element Simulations of Granular Compaction

Part
1: Roller Compaction

Matthew Brown, Matthew Pruitt, Shikha Patel, Bryan J. Ennis*

Department of Chemical
Engineering, The University of Tennessee at
Chattanooga

*Corresponding author,
bryan-j-ennis@utc.edu

Roll pressing is a common dry
granulation technique used throughout a variety of processing industries,
ranging from production of battery cathode or catalysts powders to
pharmaceutical granulate which is later tableted.  Roll pressing has several advantages over
alternative granulation techniques.  In
particular, it is a dry, continuous process, capable of recycle.  Johanson developed
an early rolling theory of compaction based on a solution of the stress
equations of equilibrium by the method of characteristics [1].  In this work, we revisit Johanson's
theory and its underlying assumptions and boundary conditions. Finite element
methods (FEM) are applied to the roller compaction for a granular continuous
media using an Arbitrary Lagrangian-Eularian (ALE)
framework.

Experimental studies by Bindhumadhavan et al.
have validated the effects of powder material properties on nip angle and peak
pressure development as predicted by Johanson's
theory.  More extensive experimental and
FEM studies were later undertaken by Cunningham et al. [2] and Balicki [3]. 
However, these previous FEM studies of roll compaction have relied on the
ABAQUS Drucker Prager plastic material model alone.

This work extends these studies
to include additional material models (both plastic and geotechnical) utilizing
LS-DYNA. Such models incorporate readily determinable material properties
measurable by shear cell and compaction measurements.  The impact of material models properties,
wall friction, gap distance and roll speed are explored, as well as the
sensitivity of press performance to these paramaters.

[1] Johanson (1965), ASME, Journal of Applied Mechanics Series
E, 32(4), 842?848)

[2] John C. Cunningham
et al. (2010), Computers & Chemical Engineering, Vol. 34, pg. 1058?1071

[3] Marcin Balicki (2003), Ecole Des Mines D'Albi Carmaux, Numerical Methods for Predicting Roll Press Powder
Compaction Parameters.