EAGER: Prototyping three-dimensional printing of sand columns for granular physics experiments

This project aims to three-dimensional print sand grains and columns that replicate the mineral moduli, elastic moduli, and microstructures of naturally-deposited sands. The investigator will collect undisturbed naturally-deposited sands, fabricate thermoplastic, glass, and powder sintered grains, fabricate sand columns composed of thermoplastic and sintered grains, and compare the material properties of fabricated and naturally-deposited sand grains and columns.

This project is exploratory and will require multiple parameter testing and/or trials and errors to refine the processes. The most high-risk high-payoff product will be printing sintered grains while preserving their microstructures. The successful development of these techniques will open several new research avenues in the micromechanics of sands, landscape evolution, and geohazard predictions.

This work also broadens the participation of three early-career black men in Geoscience. The project will create a transition to Ph.D. program that will include participating in the University of California San Diego’s Competitive Edge, which is a six-week-long program that aims to give minoritized graduate students an opportunity to begin research before the start of their graduate program and to acclimate to the campus environment.

This project will assess whether a combination of sediment collection, image processing, three-dimensional printing, and post-print techniques can produce sand grains and columns that adequately replicate the behaviors of natural sands. If successful, three dimensional printing of sand grains and columns will open new avenues of research for rock physicists, geophysicists, sedimentologists, geomorphologists, engineers, and granular physicists.

As a rock physicist and a geophysicist, some questions that 3-D printing will allow the investigator to interrogate in new ways include: (1) what is the influence of grain texture on buckling of grains, which tend to trigger landslides, liquefaction, and earthquakes? (2) what is the fundamental theory governing granular flow, which occurs during compaction, fault zone shearing, soil and hillslope creep, and contact creep aging? (3) how do grain properties control force chain distributions, which strongly influence the resistance of sands to deformation? These questions relate to several unanswered geohazard processes that we cannot predict well partly because sands’ physical properties can combine to create a vast range of mechanical behaviors.

The proposed work will inspire new research in the scientific community and bring us closer to understanding the fundamental physics that controls sands’ mechanical behaviors while helping to save or improve lives via better hazard forecasts and natural resource identification.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.