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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Gaining Insight from Data by Learning Graphical Model Structure
Abstract Not Provided
Physicochemical Heuristics for Identifying High Fidelity, Near-Native Structural Models of Peptide/M
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Simplified structure models for premixed n-alkane cool flames
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The response of a model structure to noise. part ii - curved panel
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Continuous and discrete RAE structural models.
Three dimensional coupled flexural and attitude dynamics of libration-damped cruciform gravity gradient satellite, discussing effects of orbital eccentricity, solar radiation pressure, etc
Thermal and structural modeling of superinsulation
Model permits direct physical measurement of the thermal response of critical components of space telescopes, thus providing flexibility for systems studies and design changes.
The Use of NASTRAN in the Analysis of Large Complex Airframe Structures: Modeling Techniques and Organization
Evaluation of NASTRAN system based on large complex airframe analysis
The structural modeling of aircraft tires
Aircraft tires mechanical data from small models, discussing mechanical properties, tire stresses and tire temperatures
Fragments of terra rock in the Apollo 12 soil samples and a structural model of the moon.
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A simple method for designing structural models with closely spaced modes of vibration
A simple method for designing a mathematical model with closely spaced vibration modes is described. The design process begins with a reference model having specified geometry, continuous inertia and stiffness distributions, and degrees of freedom, all of which remain unchanged. Two natural frequencies of this model are then forced together by means of systematic perturbation of the model's discrete inertia and stiffness parameters. There is only one eigenvalue solution per design cycle, and the gradient vector is calculated directly from the resulting modal quantities. The minimization procedure employed is unconstrained. As applications, a cantilevered plane grid model with five degrees of freedom and a bending-torsion-oscillator with eleven degrees of freedom are treated.
Large space structure model reduction and control system design based upon actuator and sensor influence functions
A model reduction procedure based on aggregation with respect to sensor and actuator influences rather than modes is presented for large systems of coupled second-order differential equations. Perturbation expressions which can predict the effects of spillover on both the aggregated and residual states are derived. These expressions lead to the development of control system design constraints which are sufficient to guarantee, to within the validity of the perturbations, that the residual states are not destabilized by control systems designed from the reduced model. A numerical example is provided to illustrate the application of the aggregation and control system design method.
Airplane model structure determination from flight data
Previously cited in issue 21, p. 3626, Accession no. A81-44562
Saturn's icy satellites - Thermal and structural models
Thermal history models which assume formation as homogeneous ice-silicate mixtures are constructed for the small, icy Saturnian satellites Mimas, Tethys, Dione, Rhea, and Iapetus, including the effects of radiogenic and accretional heating, conductive and subsolidus convective heat transfer, and lithosphgeric growth. Accretional heating is not likely to have melted the water ice in the interiors of these bodies, and solid state creep of the ice-dominated material precludes melting by radiogenic heating. The four largest satellites are sufficiently large and rich in heat-producing silicates to possess a solid state convection system beneath a rigid lithosphere, irrespective of initial conditions. The model thermal histories are qualitatively consistent with the present appearances of these satellites.
Space Shuttle main engine powerhead structural modeling, stress and fatigue life analysis. Volume 1: Gasdynamic environment of the SSME HPFTP and HPOTP turbines
Gasdynamic analysis for the turbine blades and nozzle vanes, HPFTP turbine analysis, and HPOTP turbine analysis are provided.
Space Shuttle main engine powerhead structural modeling, stress and fatigue life analysis. Volume 2: Dynamics of blades and nozzles SSME HPFTP and HPOTP
Normal modes of the blades and nozzles of the HPFTP and HPOTP are defined and potential driving forces for the blades are identified. The computer models used in blade analyses are described, with results. Similar information is given for the nozzles.
Space Shuttle main engine powerhead structural modeling, stress and fatigue life analysis. Volume 3: Stress summay of blades and nozzles at FPL and 115 percent RPL loads. SSME HPFTP and HPOTP blades and nozzles
Gasdynamic environments applied to the turbine blades and nozzles of the HPFTP and HPOTP were analyzed. Centrifugal loads were applied to blades to account for the pump rotation of FPL and 115 percent RPL. The computer models used in the blade analysis with results presented in the form of temperature and stress contour plots are described. Similar information is given for the nozzles.
Space Shuttle main engine, powerhead structural modeling, stress and fatigue life analysis. Volume 4: Summary of investigation of unscheduled events and special tasks
Low pressure fuel turbopump turbine labyrinth send tip rubbing analysis, gas dynamic analysis, and HPFTP blade crack and blade impact are presented.