Vol. 52, No. 3        February 11, 2000

Engineering science and systems analysis

Procurement times of GTS (Gas Transfer Systems) forgings increased to more than two years following closure of the DOE Oxnard forging facility. Procurement times will be reduced to as little as two months by changing the design and manufacture process from the trial-and-error iterations at the forging facility to optimized designs determined by computer simulations of the modeled forging process. Research in the areas of high temperature, large deformation constitutive modeling, plus advances in numerical methodologies will contribute to improve forging models and reduction in cycle times, defects, and costs. (8700, 2200) (NWSBU)

Critical to using computational models for designing and certifying weapon systems are model-validation experiments. A significant set of experiments were performed, crushing a two-staged honeycomb structure at the Area 3 Horizontal Actuator to determine the energy absorption. Honeycomb is used in the nose of the B61 to mitigate laydown forces. Experiments involved various impact speeds, impact angles, and interfacial friction. Dramatically different deformations occurred for different impact conditions. These experiments are being used to validate our computational models and discover relevant physics to be modeled. (9100) (NWSBU)

A Sandia-Purdue University team has developed and validated a unified nonlinear viscoelastic material model that provides the missing physics needed to analyze the service life of polymeric components from curing to operation. This enables modeling and simulation to predict cure shrinkage, volume and stress relaxation, yielding, and physical aging in epoxy encapsulants (e.g., neutron generators) and composite structures subjected to arbitrary thermo-mechanical histories. This is the first model ever to capture such breadth of polymer behavior. (9100, 1800, Purdue University) (NWSBU)

Sandia developed the FY2000 Implementation Plan for Advanced Simulation and Computing. The two-volume document, the first ever to link project task and milestones, reports on funded projects (at the three defense labs and Y-12 Plant) in five programmatic areas: (1) Defense Applications and Modeling, (2) Simulation and Computer Science, (3) Integrated Computing Systems, (4) University Partnerships, and (5) ASCI Special Projects. There were numerous contributors from each defense lab and DOE. (9100, 9900) (NWSBU)

A team of Sandia fire scientists, code developers, and experimentalists is changing the culture of the DoD and DOE communities responsible for the safety and survivability of assets exposed to fire. The team has researched critical fire physics issues, distilled that knowledge into a numerical simulation (VULCAN), and conducted experiments to understand the important physics and check VULCAN predictions. This team has demonstrated to a test-based world the power of simulation-based engineering to solve complex problems. (9100) (NWSBU; S&T SMU)

Last modified: February 28, 2000

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