Civil and Environmental Engineering Department Seminar: Granular Mechanics: Soil, Additive Manufacturing, and Beyond

Seminar | March 18 | 10-11 a.m. | 542 Davis Hall

 Michelle Bernhardt-Barry

 Civil and Environmental Engineering (CEE)

The advent of additive manufacturing (AM) has opened many new fields of study related to multi-scale granular material behavior and it has the potential to transform the way in which we design and construct geotechnical infrastructure. This talk will highlight several areas of ongoing research within Dr. Bernhardt-Barry’s group and opportunities for expanding this research in the future. The first area will focus on the use of additively manufactured particles to better understand multi-scale granular soil behavior. Using AM, analogue soils are produced and tested in the laboratory using traditional geotechnical experimental devices. This provides a means to examine the influence of particle shape on the strength of a granular soil while maintaining constant material properties and surface characteristics, something not possible with natural sands. The material properties for these analogue soils are also be obtained through laboratory testing, providing the grain properties needed in discrete element method (DEM) models. Results from this work will be presented to show the use of AM analogue soils through the material characterization and laboratory testing phases. A second area flips the focus to the use of granular mechanics to better understand the AM processes themselves. Many AM devices create 3D parts in a layer-by-layer process in which powders of various material compositions are either sintered or chemically bound. The quality of the resulting part has been shown to depend highly on the powder characteristics, deposition of the powder, and the interactions and packing of the layers of powder during spreading. Because it is difficult to fully gain this quantitative knowledge through experiments alone, DEM simulations provide a particle-scale approach capable of examining these behaviors and interactions. Results from experimentally calibrated DEM simulations are presented to show the particle kinematics and particle packing observed during the AM spreading process. The final area of discussion will focus on future uses of AM for transforming the way in which we view, design, and construct infrastructure. A brief discussion of Dr. Bernhardt-Barry’s NSF CAREER project will be given along with future opportunities for research in these areas.

 Leori Gill, CA, leorig@berkeley.edu, 510-642-1762