Sandia Labs FY21 LDRD Annual Report

FY21 ANNUAL REPORT

standardize the technique across the field, and actively leads efforts to train and certify DIC users on the technique, with courses being attended by scientists with Sandia, other NNSA labs, and the DoD. Sandia leads on the DIC Challenge, providing images and analysis for DIC code comparisons and improvement for users around the world. At Sandia, LDRD advanced the state-of-the-art of DIC by both applying the technique to new domains and developing new techniques altogether. LDRD investments have: • Improved how material models and material properties are determined via optimized test specimen design, novel inverse techniques, and full-field displacement data from DIC. • Enabled the development and first-time demonstration of high-speed X-ray DIC in a harsh aerodynamic environment, thus improving measurements of the response of critical components to dynamic environments. • Led the first successful demonstration of many advanced imaging diagnostics within post-detonation environments, improving models that help researchers understand fragment and fireball dynamics. Impacts from the capability development are broad. For example, DoD Joint Live Fire is adopting DIC for model validation for munitions models, and full-field model validation is now used on many non- nuclear weapons components. • Helped nurture early career talent in the engineering sciences at Sandia. For example, early career researcher Caroline Winters contributed to numerous DIC LDRD research projects at Sandia. Winters says, “As a PI of an Exploratory Express LDRD project during my postdoc appointment and then reprising the role of PI for a full Engineering Sciences LDRD a year after transitioning to staff, LDRD has been pivotal to defining my technical path at Sandia. Through both the sponsored programming and the generous time given by the LDRD Investment Area team members, I have accelerated my technical writing, innovation, project management, and networking internal and external to Sandia.”

Caroline Winters Winters is developing new DIC techniques as she leads an LDRD project that started in 2021. The work is investigating how to provide a “full” time-resolved and 3D picture of a test article undergoing combined, thermal-mechanical environments. Since tests are often conducted in occluded environments, like sooty pool fires, seeing in with X-rays is key to measuring strain, deformation, and temperature. Multi-planar X-ray DIC—an effort led by early career LDRD researchers Elizabeth Jones and Ben Halls—has extended the information we can infer from a single X-ray image. Specifically, we can now measure strain in multiple planes of motion, simultaneously, through both innovative patterning and novel data processing algorithms.”

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LABORATORY DIRECTED RESEARCH & DEVELOPMENT