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A Method to Capture Macroslip at Bolted Interfaces [PowerPoint]

Hopkins, Ronald N.; Heitman, Lili A.

Relative motion at bolted connections can occur for large shock loads as the internal shear force in the bolted connection overcomes the frictional resistive force. This macroslip in a structure dissipates energy and reduces the response of the components above the bolted connection. There is a need to be able to capture macroslip behavior in a structural dynamics model. A linear model and many nonlinear models are not able to predict marcoslip effectively. The proposed method to capture macroslip is to use the multi-body dynamics code ADAMS to model joints with 3-D contact at the bolted interfaces. This model includes both static and dynamic friction. The joints are preloaded and the pinning effect when a bolt shank impacts a through hole inside diameter is captured. Substructure representations of the components are included to account for component flexibility and dynamics. This method was applied to a simplified model of an aerospace structure and validation experiments were performed to test the adequacy of the method.

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TYPE Conference Poster YEAR 2016
OSTIDOI

A Method to Capture Macroslip at Bolted Interfaces

Hopkins, Ronald N.; Heitman, Lili A.

Relative motion at bolted connections can occur for large shock loads as the internal shear force in the bolted connection overcomes the frictional resistive force. This macroslip in a structure dissipates energy and reduces the response of the components above the bolted connection. There is a need to be able to capture macroslip behavior in a structural dynamics model. A linear model and many nonlinear models are not able to predict marcoslip effectively. The proposed method to capture macroslip is to use the multi-body dynamics code ADAMS to model joints with 3-D contact at the bolted interfaces. This model includes both static and dynamic friction. The joints are preloaded and the pinning effect when a bolt shank impacts a through hole inside diameter is captured. Substructure representations of the components are included to account for component flexibility and dynamics. This method was applied to a simplified model of an aerospace structure and validation experiments were performed to test the adequacy of the method.

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TYPE Conference Poster YEAR 2015
OSTIDOI

Technical Assistance for Southwest Solar Technologies Inc. Final Report

Bauer, Stephen J.; Heitman, Lili A.

Southwest Solar Technologies Inc. is constructing a Solar-Fuel Hybrid Turbine energy system. This innovative energy system combines solar thermal energy with compressed air energy storage and natural gas fuel backup capability to provide firm, non-intermittent power. In addition, the energy system will have very little impact on the environment since, unlike other Concentrated Solar Power (CSP) technologies, it requires minimal water. In 2008 Southwest Solar Technologies received a Solar America Showcase award from the Department of Energy for Technical Assistance from Sandia National Laboratories. This report details the work performed as part of the Solar America Showcase award for Southwest Solar Technologies. After many meetings and visits between Sandia National Labs and Southwest Solar Technologies, several tasks were identified as part of the Technical Assistance and the analysis and results for these are included here.

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TYPE SAND Report YEAR 2012
OSTIDOI

PAT-1 safety analysis report addendum

Yoshimura, Richard H.; Morrow, Charles W.; Weiner, Ruth F.; Harding, David C.; Heitman, Lili A.; Kalan, Robert K.; Lopez Mestre, Carlos L.; Miller, David R.; Schmale, David T.; Knorovsky, Gerald A.

The Plutonium Air Transportable Package, Model PAT-1, is certified under Title 10, Code of Federal Regulations Part 71 by the U.S. Nuclear Regulatory Commission (NRC) per Certificate of Compliance (CoC) USA/0361B(U)F-96 (currently Revision 9). The purpose of this SAR Addendum is to incorporate plutonium (Pu) metal as a new payload for the PAT-1 package. The Pu metal is packed in an inner container (designated the T-Ampoule) that replaces the PC-1 inner container. The documentation and results from analysis contained in this addendum demonstrate that the replacement of the PC-1 and associated packaging material with the T-Ampoule and associated packaging with the addition of the plutonium metal content are not significant with respect to the design, operating characteristics, or safe performance of the containment system and prevention of criticality when the package is subjected to the tests specified in 10 CFR 71.71, 71.73 and 71.74.

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TYPE SAND Report YEAR 2010
OSTIDOI

PAT-1 safety analysis report addendum author responses to request for additional information

Yoshimura, Richard H.; Knorovsky, Gerald A.; Morrow, Charles W.; Weiner, Ruth F.; Harding, David C.; Heitman, Lili A.; Lopez Mestre, Carlos L.; Kalan, Robert K.; Miller, David R.; Schmale, David T.

The Plutonium Air Transportable Package, Model PAT-1, is certified under Title 10, Code of Federal Regulations Part 71 by the U.S. Nuclear Regulatory Commission (NRC) per Certificate of Compliance (CoC) USA/0361B(U)F-96 (currently Revision 9). The National Nuclear Security Administration (NNSA) submitted SAND Report SAND2009-5822 to NRC that documented the incorporation of plutonium (Pu) metal as a new payload for the PAT-1 package. NRC responded with a Request for Additional Information (RAI), identifying information needed in connection with its review of the application. The purpose of this SAND report is to provide the authors responses to each RAI. SAND Report SAND2010-6106 containing the proposed changes to the Addendum is provided separately.

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TYPE SAND Report YEAR 2010
OSTIDOI

A stress-state modified strain based failure criterion for evaluating the structural integrity of an inner eutectic barrier

Heitman, Lili A.; Yoshimura, Richard H.; Miller, David R.

A slight modification of a package to transport solid metal contents requires inclusion of a thin titanium liner to protect against possible eutectic formation in 10 CFR 71.74 regulatory fire accident conditions. Under severe transport regulatory impact conditions, the package contents could impart high localized loading of the liner, momentarily pinching it between the contents and the thick containment vessel, and inducing some plasticity near the contact point. Actuator and drop table testing of simulated contents impacts against liner/containment vessel structures nearly bounded the potential plastic strain and stress triaxiality conditions, without any ductile tearing of the eutectic barrier. Additional bounding was necessary in some cases beyond the capability of the actuator and drop table tests, and in these cases a stress-modified evolution integral over the plastic strain history was successfully used as a failure criterion to demonstrate that structural integrity was maintained. The Heaviside brackets only allow the evolution integral to accumulate value when the maximum principal stress is positive, since failure is never observed under pure hydrostatic pressure, where the maximum principal stress is negative. Detailed finite element analyses of myriad possible impact orientations and locations between package contents and the thin eutectic barrier under regulatory impact conditions have shown that not even the initiation of a ductile tear occurs. Although localized plasticity does occur in the eutectic barrier, it is not the primary containment boundary and is thus not subject to ASME stress allowables from NRC Regulatory Guide 7.6. These analyses were used to successfully demonstrate that structural integrity of the eutectic barrier was maintained in all 10 CFR 71.73 and 71.74 regulatory accident conditions. The NRC is currently reviewing the Safety Analysis Report.

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TYPE Conference YEAR 2010
OSTI
Results 1–25 of 29
Results 1–25 of 29