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Recent advances in a 10-node composite tetrahedral element for solid mechanics.
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Modeling Shock in Solids Using a 10-Node Composite Tetrahedral Element
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Constructing Tetrahedral Meshes no Matter How Ugly the CAD
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Modeling Shock in Solids Using a 10-Node Composite Tetrahedral Element
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Advances in a 10-node composite tetrahedral framework for shock and mesh adaptivity
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Strategies for the incremental improvement of highly deformed, 10-noded composite tetrahedral meshes in contact
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Advances in a 10-node composite tetrahedral framework for shock and mesh adaptivity
Presenting this work at USNCCM
Source Data for Calculations, UV-vis-NIR, and NMR for A Tetrahedral Neptunium(V) Complex
Data associated with the Nature Chemistry publication (DOI: 10.1038/s41557-024-01529-6 ) was made publicly available in a FigShare repository (10.6084/m9.figshare.24309463) to ensure reproducibility and support the PI's commitment to open-science that was included in the data management plan of the project
Intermolecular forces in globular molecules. VI - Octopole moments of tetrahedral molecules.
Octopole moments for methane and carbon tetrafluoride derived from second virial coefficients temperature dependence, using spherical shell potential model
The bonding of ferrous iron to sulfur and oxygen in tetrahedral coordination - A comparative study using SCF X alpha scattered wave molecular orbital calculations
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Collision-broadened line widths of tetrahedral molecules. I - Theoretical formulation
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Collision-broadened linewidths of tetrahedral molecules. II - Computations for CH4 lines broadened by N2, O2, He, Ne and Ar
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High pressure phase transitions in tetrahedrally coordinated semiconducting compounds
New experimental results are reported for structural transitions at high pressure in several III-V compounds and two II-VI compounds. These data, together with earlier results, are then compared with the predictions of model calculations of Van Vechten. Experimental transition pressures are often at variance with calculated values. However, his calculation assumes that the high pressure phase is metallic, with the beta-Sn structure. The present results show that several compounds assume an ionic NaCl structure at high pressure, while others have neither the beta-Sn nor NaCl structure.
Deployment tests of a 36-element tetrahedral truss module
In the past, models of deployable structures were limited largely to small scale models which could be readily deployed by suspending the model on several soft shock cords. The scale of the deployable truss used in the present investigation precluded the use of this test technique as the gravity forces and moments are of the same order of magnitude as the deployment forces and moments. For these tests, the truss was deployed during free-fall in the LaRC 55' vacuum facility. Appreciably larger trusses could be deployed by lofting the packaged truss upward from the floor of the facility and allowing it to deploy during the upward as well as the downward portion of its trajectory, thus doubling the available test time. It must be realized, of course, that the mechanisms required to loft and decelerate such a large truss would be much more complex than those required for a straight drop.
Preliminary design of tetrahedral truss reflector structure
A baseline structure proposed for the microwave radiometer spacecraft (MRS) reflector is a large graphite-epoxy truss. The truss structure was selected to provide adequate stiffness to minimize control problems and to provide a low-expansion 'strong back' on which to mount and control reflector mesh panels. Details of the structural members, joints and assembly concepts are presented, a concept for the reflector mesh surface is discussed, and preliminary estimates of the mass and structural natural frequencies of the reflector system are presented.
Mobile remote manipulator system for a tetrahedral truss
The mobile remote manipulator system (MRMS) was initially developed for transit about the trusses of the delta space station; however, it can be utilized just as easily for transit about the trusses of the dual keel station. The MRMS is comprised of a mobile platform having a rail system formed of transversely disposed T-shaped tracks, which engage with guide pins located at the nodes of the trusses. The guide pins form a grid and the tracks are so designed as to permit travel in either of two orthogonal directions. The present invention provides a near-uniform traversing velocity with minimal dynamic loading on the system. Pivoting changers move the platform from one face to another.
Spatial adaptation procedures on tetrahedral meshes for unsteady aerodynamic flow calculations
Spatial adaptation procedures for the accurate and efficient solution of steady and unsteady inviscid flow problems are described. The adaptation procedures were developed and implemented within a three-dimensional, unstructured-grid, upwind-type Euler code. These procedures involve mesh enrichment and mesh coarsening to either add points in high gradient regions of the flow or remove points where they are not needed, respectively, to produce solutions of high spatial accuracy at minimal computational cost. A detailed description of the enrichment and coarsening procedures are presented and comparisons with experimental data for an ONERA M6 wing and an exact solution for a shock-tube problem are presented to provide an assessment of the accuracy and efficiency of the capability. Steady and unsteady results, obtained using spatial adaptation procedures, are shown to be of high spatial accuracy, primarily in that discontinuities such as shock waves are captured very sharply.