Purdue University, USA
Multi-scale modeling and simulation of microstructure formation and evolution during powder compaction
Powder compaction plays a relevant role in many pharmaceutical, energetic material, 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., elasto-plastic deformations, adhesion, bonding, friction, and fracture) that govern the properties and performance of the final product (e.g., tablet hardness, swelling and disintegration for pharmaceutical powders pressed into solid tablets for oral administration; and formation and growth of hot spots under impact conditions for energetic composite materials). 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 three 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. Third, the experimental characterization of particle’s mechano-chemical properties required in the model. In this talk, I will present progress in these three fronts, including: (i) nonlocal contact formulations that overcome the typical, but unrealistic, assumption that contacts are independent regardless the confinement of the granular system, (ii) a particle mechanics approach which concurrently solves for contact forces at the granular scale, for nonlocal deformations at the mesoscale, and for static equilibrium at the macroscale, (iii) characterization techniques that utilize modeling and experimental methodologies in lockstep coordination with each other at the particle scale.
Dr. Marcial Gonzalez is an Assistant Professor in the School of Mechanical Engineering at Purdue University since 2014, and he is a co-Director of the Particle, Powder, and Compact Characterization Laboratory. 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 performance. Application areas of interest include: consolidation and compaction of powders, and performance of pharmaceutical solid products (e.g., tensile strength, stiffness, swelling and disintegration) and energetic materials (e.g., deformation and heat generation under impact conditions, and formation and growth of hot spots). These studies are achieved by a combined experimental and multi-scale modeling effort that systematically uses a micro-compression testing machine (for making measurements at the particle scale), an instrumented compaction simulator (for characterizing the compaction process) and a supercomputer cluster (ranked the nation’s fastest university-owned supercomputer in 2013).