Sandia Labs FY22 Laboratory Directed Research & Development Annual Report

FY22 ANNUAL REPORT

UNDERSTANDING MOLECULAR-SCALE EFFECTS ON FRACTURE CAN INFORM RESOURCE EXTRACTION AND HELP MAINTAIN THE NATION’S INFRASTRUCTURE. Subcritical fracture controls deformation and permeability of rocks and degradation of manmade dependency during nanoindentation of laminated crystals. The experiments and models indicated that while calcium oxide phases are extremely sensitive to the presence of water, calcium

materials. To further understand the chemical mechanisms controlling subcritical fracture, this three-year project created nanomechanical and continuum-scale mechanics experiments to assess elastic, plastic, and brittle deformation of single crystals and multi-component rocks in reactive chemical environments. Additionally, Sandia researchers developed atomistic and continuum-scale modeling approaches to predict fracturing in silicate, carbonate, and oxide solids, mimicking those reactive environments. The team, in conjunction with Sandia Alliance partner University of Illinois at Urbana-Champaign is developing a new data analysis tool to assess scale

carbonate undergoes only mild water-weakening and ion-specific interactions that can significantly decrease fracturing. Understanding molecular scale effects on fracture could revolutionize the nation’s use of subsurface systems for resource extraction, storage of CO 2 and nuclear waste, and help maintain essential infrastructure relevant to national security. The project’s findings to date are reported in Journal of Materials Science , The Journal of Physical Chemistry C , and Physical Review E . (PI: Anastasia G. Ilgen)

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(a) Liquid nanoindentation setup, (b) indentation site for individual grain, and (c) water inside crack tip in molecular dynamics simulations.

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