Multi-scale Modeling and Simulation of Powder Compaction

Event Date: April 14, 2014
Speaker: Professor Marcial Gonzalez
Speaker Affiliation: Assistant Professor, Purdue School of Mechanical Engineering
Sponsor: School of Materials Engineering
Time: 3:30pm Coffee, 3:45pm Seminar
Location: ARMS 1010

Powder compaction plays a relevant role in many pharmaceutical, food, ceramic and metallurgical manufacturing processes, so much so that microstructure evolution during consolidation has direct impact on the end-product properties and performance. This process involves a variety of coupled physical mechanisms at the particle-scale (e.g., elastoplastic deformations, adhesion, bonding, friction, and fracture) that govern the properties and performance of the final product (i.e., tablet hardness and drug delivery profile for pharmaceutical powders pressed into solid tablets for oral administration). Therefore, it is of paramount importance to fundamentally understand these coupled mechanisms in order to optimize manufacturing processes and to improve product design.

Predictive multi-scale modeling and simulation of microstructure formation and evolution during compaction of granular solids requires research efforts in two main fronts. First, the development of predictive constitutive models of inter-particle interactions that account for high levels of confinement and a variety of physical mechanisms. Second, the development of concurrent multi-scale strategies that combine a detailed description of the granular scale with the computational efficiency typical of continuum-level models. In this Seminar I will present progress in these two fronts, including: (i) a new 'nonlocal contact formulation' that overcomes the typical, but unrealistic, assumption that contacts are independent regardless the confinement of the granular system, (ii) a fully-discrete model which concurrently solves for contact forces at the granular scale, for nonlocal deformations at the mesoscale, and for static equilibrium at the macroscale. The ability of these models to shed light on the broader question of how amorphous solids support stress will also be addressed.

The remaining of the talk I will address the challenge of predicting product performance. Specifically, I will show how strength predictions can be obtained by a seamless extension of the fully-discrete model to elasto-plastic deformations and bonding mechanisms.

Dr. Marcial Gonzalez is an Assistant Professor in the School of Mechanical Engineering at Purdue University since 2014. He was a Research Associate at Rutgers University with an affiliation with the Mechanical and Aerospace Engineering Department and with the NSF Engineering Research Center for Structured Organic Particulate Systems. He received his Ph.D. in Aeronautics, with a minor in Materials Science, from the California Institute of Technology in 2010. He is a Mechanical Engineer from the University of Buenos Aires, Argentina, and received a MS in Aeronautics from Caltech. His current research focuses on predictive, multi-scale modeling and simulation of microstructure evolution in confined granular systems, with an emphasis in manufacturing processes and the relationship between product fabrication and operation. Prior to beginning his doctoral studies, he worked five years as a Research Engineer in Tenaris, a world-leader manufacturer of seamless steel pipes for the energy industry.