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Parallel Solver Framework for Mixed-Integer PDE-Constrained Optimization

Phillips, Cynthia A.; Chatter, Michelle; Eckstein, Jonathan; Erturk, Alper; El-Kady, Ihab F.; Gerbe, Romain; Kouri, Drew P.; Loughlin, William; Reinke, Charles M.; Rokkam, Rohith; Ruzzene, Massimo; Sugino, Christopher; Swanson, Calvin; Van Bloemen Waanders, Bart

ROL-PEBBL is a C++, MPI-based parallel code for mixed-integer PDE-constrained optimization (MIPDECO). In these problems we wish to optimize (control, design, etc.) physical systems, which must obey the laws of physics, when some of the decision variables must take integer values. ROL-PEBBL combines a code to efficiently search over integer choices (PEBBL = Parallel Enumeration Branch-and-Bound Library) and a code for efficient nonlinear optimization, including PDE-constrained optimization (ROL = Rapid Optimization Library). In this report, we summarize the design of ROL-PEBBL and initial applications/results. For an artificial source-inversion problem, finding sources of pollution on a grid from sparse samples, ROL-PEBBLs solution for the nest grid gave the best optimization guarantee for any general solver that gives both a solution and a quality guarantee.

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TYPE SAND Report YEAR 2021
DOIOSTI

Massively Parallel Capability in Sierra/SD for Simulation Vibration with Piezoelectrics

Bunting, Gregory; Smith, Chandler; Walsh, Timothy

Sierra/SD is an engineering structural dynamics code that provides Sandia and other customers a tool to model structural and acoustic physics on large complex physical systems using massively parallel processing. This report provides a detailed overview on Sierra/SD’s most recent physics package: coupled electro-mechanical physics. This capability uses the finite element method to model coupled electro-mechanical physics exhibited by piezoelectric materials. This report provides an applications overview, theory overview, and verification examples demonstrating the electro-mechanical physics modeling capabilities of Sierra/SD.

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TYPE SAND Report YEAR 2021
DOIOSTI

Innovation

Ackermann, Mark R.

Innovation is a highly overused buzzword in government offices and corporate America. Just like leadership, innovation is something that organizations realize they need, but often are frustrated in their efforts to achieve. Making matters worse, the definition of innovation changes with the user and the context. Simply put, innovation is change and change for any organization is difficult. This study examines the topic of innovation and pays special attention to what works, what does not work, and the basic principles governing how one might go about innovating. As leadership is critical to any successful innovation effort, special attention is given to leading change and leading innovation. ''The reasonable man adapts himself to the world; the unreasonable one persists to adapt the world to himself. Therefore, all progress depends on the unreasonable man.'' - George Bernard Shaw

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TYPE SAND Report YEAR 2021
DOIOSTI

Structure-Property Relationships of Additively Manufactured Ni-Nb Alloys [Slides]

Jones, Morgan; Kustas, Andrew B.; Delrio, F.W.; Pegues, Jonathan W.; Lu, Ping; Chandross, Michael E.; Argibay, Nicolas

In this work, scratch and nanoindentation testing was used to determine hardness, fracture toughness, strain rate sensitivity, and activation volumes on additively manufactured graded and uniform Ni-Nb bulk specimens. Characterization showed the presence of a two phase system consisting of Ni3Nb and Ni6Nb7 intermetallics. Intermetallics were multimodal in nature, having grain and cell sizes spanning from a few nanometers to 10s of micrometers. The unique microstructure resulted in impressively high hardness, up to 20 GPa in the case of the compositionally graded sample. AM methods with surface deformation techniques are a useful way to rapidly probe material properties and alloy composition space.

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TYPE Conference Presenation YEAR 2021
DOIOSTI

DPC Direct Disposal R&D Independent Technical Review: Plan

Hardin, Ernest

Developing and evaluating approaches for direct geologic disposal of commercial spent nuclear fuel (SNF) in dual-purpose canisters (DPCs) is a cross-cutting multi-disciplinary activity that is directly tied to the implementation of DPCs by the nuclear industry. The ultimate goal of the DPC direct disposal R&D program is to facilitate and maximize safe, cost-effective, licensed direct disposal. Independent Technical Review (ITR) is needed to maximize the impact of the R&D program on future implementation. The review will involve a team of experts representing the nuclear industry, repository sciences, and licensing. The team will be charged to review a set of representative technical reports and other information, and answer a set of questions that focus on R&D steering.

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TYPE Other Report YEAR 2021
DOIOSTI

Rapid QSTS Simulations for High-Resolution Comprehensive Assessment of Distributed PV

Broderick, Robert J.; Reno, Matthew J.; Lave, Matt; Azzolini, Joseph A.; Blakely, Logan; Galtieri, Jason; Mather, Barry; Weekley, Andrew; Hunsberger, Randolph; Chamana, Manohar; Li, Qinmiao; Zhang, Wenqi; Latif, Aadil; Zhu, Xiangqi; Grijalva, Santiago; Zhang, Xiaochen; Deboever, Jeremiah; Qureshi, Muhammad U.; Therrien, Francis; Lacroix, Jean-Sebastien; Li, Feng; Belletete, Marc; Hebert, Guillaume; Montenegro, Davis; Dugan, Roger

The rapid increase in penetration of distributed energy resources on the electric power distribution system has created a need for more comprehensive interconnection modeling and impact analysis. Unlike conventional scenario-based studies, quasi-static time-series (QSTS) simulations can realistically model time-dependent voltage controllers and the diversity of potential impacts that can occur at different times of year. However, to accurately model a distribution system with all its controllable devices, a yearlong simulation at 1-second resolution is often required, which could take conventional computers a computational time of 10 to 120 hours when an actual unbalanced distribution feeder is modeled. This computational burden is a clear limitation to the adoption of QSTS simulations in interconnection studies and for determining optimal control solutions for utility operations. The solutions we developed include accurate and computationally efficient QSTS methods that could be implemented in existing open-source and commercial software used by utilities and the development of methods to create high-resolution proxy data sets. This project demonstrated multiple pathways for speeding up the QSTS computation using new and innovative methods for advanced time-series analysis, faster power flow solvers, parallel processing of power flow solutions and circuit reduction. The target performance level for this project was achieved with year-long high-resolution time series solutions run in less than 5 minutes within an acceptable error.

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TYPE SAND Report YEAR 2021
DOIOSTI

Library of Advanced Materials for Engineering (LAMÉ) 5.0

Lester, Brian T.; Scherzinger, William M.; Long, Kevin N.; Reedlunn, Benjamin; Vignes, Chet

Accurate and efficient constitutive modeling remains a cornerstone issue for solid mechanics analysis. Over the years, the LAMÉ advanced material model library has grown to address this challenge by implementing models capable of describing material systems spanning soft polymers to stiff ceramics including both isotropic and anisotropic responses. Inelastic behaviors including (visco)plasticity, damage, and fracture have all incorporated for use in various analyses. This multitude of options and flexibility, however, comes at the cost of many capabilities, features, and responses and the ensuing complexity in the resulting implementation. Therefore, to enhance confidence and enable the utilization of the LAMÉ library in application, this effort seeks to document and verify the various models in the LAMÉ library. Specifically, the broader strategy, organization, and interface of the library itself is first presented. The physical theory, numerical implementation, and user guide for a large set of models is then discussed. Importantly, a number of verification tests are performed with each model to not only have confidence in the model itself but also highlight some important response characteristics and features that may be of interest to end-users. Finally, in looking ahead to the future, approaches to add material models to this library and further expand the capabilities are presented

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TYPE SAND Report YEAR 2021
DOIOSTI
Results 13001–13100 of 99,299
Results 13001–13100 of 99,299