Sandia Labs FY21 LDRD Annual Report

FY21 ANNUAL REPORT

ASCeND project provides mathematical tools to discretize models. Nonlocal models, which describe a system via integral operators acting over a finite length scale, provide a unique ability to describe mechanics of interest to DOE, but face technical hurdles that prevent broader adoption. The ASymptotically Compatible strong form foundations for Nonlocal Discretization (ASCeND) project developed mathematical tools for discretizing these models that preserve notions of asymptotic compatibility, whereby the solution will recover classical theory as a nonlocal parameter is reduced to zero. Guided by this objective, the team developed mathematics that maximize impact to mission

exemplars related to ductile fracture and energy storage devices fracture. (PI: Nat Trask)

Exemplar problems: (1) Large deformation ductile fracture. (2) Transport induced brittle fracture and lithiation-induced failure of Li-ion batteries.

Novel detection mechanisms assess aerosol-cloud interactions. Ship tracks are quasi-linear cloud patterns produced from the interaction of ship emissions with low boundary-layer clouds. They are visible throughout the diurnal cycle in satellite images from space-borne assets like the Advanced Baseline Imagers aboard the National Oceanic and Atmospheric Administration (NOAA) Geostationary Operational Environmental Satellites (GOES). Complex atmospheric dynamics, however, often make it difficult to identify and characterize the formation and evolution of tracks. Ship tracks could increase a cloud’s albedo and reduce the impact of global warming. Thus, it is important to study these patterns not only to better understand the complex atmospheric interactions between aerosols and clouds to improve climate models, but also to examine the efficacy of climate interventions,

such as marine cloud brightening. During this LDRD project, the team developed novel data- driven techniques that advance our ability to assess the effects of ship emissions on marine environments and the risks of future marine cloud brightening efforts. The three main innovative technical contributions include a method to track aerosol injections using optical flow, a stochastic simulation model for track formations, and an automated detection algorithm for efficient identification of ship tracks in large datasets. (PI: Lyndsay Shand)

(Left) Ship tracks in action. (Right) Ship tracks as seen in NOAA GOES-17 imagery.

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LABORATORY DIRECTED RESEARCH & DEVELOPMENT