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Automated high-throughput tensile testing reveals stochastic process parameter sensitivity

Materials Science and Engineering: A

Heckman, Nathan H.; Ivanoff, Thomas I.; Roach, Ashley M.; Jared, Bradley H.; Tung, Daniel J.; Huber, Todd H.; Saiz, David J.; Koepke, Joshua R.; Rodelas, Jeffrey R.; Madison, Jonathan D.; Salzbrenner, Bradley S.; Swiler, Laura P.; Jones, Reese E.; Boyce, Brad B.

The mechanical properties of additively manufactured metals tend to show high variability, due largely to the stochastic nature of defect formation during the printing process. This study seeks to understand how automated high throughput testing can be utilized to understand the variable nature of additively manufactured metals at different print conditions, and to allow for statistically meaningful analysis. This is demonstrated by analyzing how different processing parameters, including laser power, scan velocity, and scan pattern, influence the tensile behavior of additively manufactured stainless steel 316L utilizing a newly developed automated test methodology. Microstructural characterization through computed tomography and electron backscatter diffraction is used to understand some of the observed trends in mechanical behavior. Specifically, grain size and morphology are shown to depend on processing parameters and influence the observed mechanical behavior. In the current study, laser-powder bed fusion, also known as selective laser melting or direct metal laser sintering, is shown to produce 316L over a wide processing range without substantial detrimental effect on the tensile properties. Ultimate tensile strengths above 600 MPa, which are greater than that for typical wrought annealed 316L with similar grain sizes, and elongations to failure greater than 40% were observed. It is demonstrated that this process has little sensitivity to minor intentional or unintentional variations in laser velocity and power.

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SECURE: An Evidence-based Approach to Cyber Experimentation

Proceedings - 2019 Resilience Week, RWS 2019

Pinar, Ali P.; Benz, Zachary O.; Castillo, Anya; Hart, William E.; Swiler, Laura P.; Tarman, Thomas D.

Securing cyber systems is of paramount importance, but rigorous, evidence-based techniques to support decision makers for high-consequence decisions have been missing. The need for bringing rigor into cybersecurity is well-recognized, but little progress has been made over the last decades. We introduce a new project, SECURE, that aims to bring more rigor into cyber experimentation. The core idea is to follow the footsteps of computational science and engineering and expand similar capabilities to support rigorous cyber experimentation. In this paper, we review the cyber experimentation process, present the research areas that underlie our effort, discuss the underlying research challenges, and report on our progress to date. This paper is based on work in progress, and we expect to have more complete results for the conference.

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Status Report on Uncertainty Quantification and Sensitivity Analysis Tools in the Geologic Disposal Safety Assessment (GDSA) Framework

Swiler, Laura P.; Helton, J.C.; Basurto, Eduardo B.; Brooks, Dusty M.; Mariner, Paul M.; Moore, Leslie M.; Mohanty, Sitakanta N.; Sevougian, Stephen D.; Stein, Emily S.

The Spent Fuel and Waste Science and Technology (SFWST) Campaign of the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), Office of Fuel Cycle Technology (FCT) is conducting research and development (R&D) on geologic disposal of spent nuclear fuel (SNF) and high-level nuclear waste (HLW). Two high priorities for SFWST disposal R&D are design concept development and disposal system modeling. These priorities are directly addressed in the SFWST Geologic Disposal Safety Assessment (GDSA) control account, which is charged with developing a geologic repository system modeling and analysis capability, and the associated software, GDSA Framework, for evaluating disposal system performance for nuclear waste in geologic media. GDSA Framework is supported by SFWST Campaign and its predecessor the Used Fuel Disposition (UFD) campaign.

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Progress in Deep Geologic Disposal Safety Assessment in the U.S. since 2010

Mariner, Paul M.; Connolly, Laura A.; Cunningham, Leigh C.; Debusschere, Bert D.; Dobson, David C.; Frederick, Jennifer M.; Hammond, Glenn E.; Jordan, Spencer H.; LaForce, Tara; Nole, Michael A.; Park, Heeho D.; Laros, James H.; Rogers, Ralph D.; Seidl, Daniel T.; Sevougian, Stephen D.; Stein, Emily S.; Swift, Peter N.; Swiler, Laura P.; Vo, Jonathan; Wallace, Michael G.

The Spent Fuel and Waste Science and Technology (SFWST) Campaign of the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), Office of Spent Fuel & Waste Disposition (SFWD) is conducting research and development (R&D) on geologic disposal of spent nuclear fuel (SNF) and high-level nuclear waste (HLW). Two high priorities for SFWST disposal R&D are design concept development and disposal system modeling (DOE 2011, Table 6). These priorities are directly addressed in the SFWST Geologic Disposal Safety Assessment (GDSA) work package, which is charged with developing a disposal system modeling and analysis capability for evaluating disposal system performance for nuclear waste in geologic media.

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Gaussian-Process-Driven Adaptive Sampling for Reduced-Order Modeling of Texture Effects in Polycrystalline Alpha-Ti

JOM

Tallman, Aaron E.; Stopka, Krzysztof S.; Swiler, Laura P.; Wang, Yan; Kalidindi, Surya R.; Mcdowell, David L.

Data-driven tools for finding structure–property (S–P) relations, such as the Materials Knowledge System (MKS) framework, can accelerate materials design, once the costly and technical calibration process has been completed. A three-model method is proposed to reduce the expense of S–P relation model calibration: (1) direct simulations are performed as per (2) a Gaussian process-based data collection model, to calibrate (3) an MKS homogenization model in an application to α-Ti. The new methods are compared favorably with expert texture selection on the performance of the so-calibrated MKS models. Benefits for the development of new and improved materials are discussed.

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Results 51–75 of 336
Results 51–75 of 336