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  • 1
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    The 15 meter hoop-column antenna dynamics: Test and analysis (1986)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A 15 meter model of the hoop-column antenna concept has been vibration tested for model characterization and analytical model verification. Linear finite element analysis predicted the global vibration frequencies accurately. Good agreement between analysis and test data was obtained only after the analytical model was refined using static test data. As structures become more flexible, structural properties determined from static data become more accurate and should be used to update analytical models. Global vibration modes are not significantly affected by the surface mesh which permits simplified analytical models to be used for prediction of global behavior. These reduced models are believed sufficient for preliminary design and controls simulations where only global behavior is desired. The mesh modes were highly damped due to the knit mesh used for the reflector surface. These modes were also highly coupled and very difficult to measure in the laboratory. The inability to fully characterize the antenna mesh modes in the laboratory indicates robust methods for active surface vibration suppression will be needed. Fortunately, the surface mesh exhibits high passive damping which should be beneficial to active control systems.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA(DOD Control)Structures Interaction Technology, 1986; p 167-185
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  • 2
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    Quasistatic shape adjustment of a 15-meter-diameter space antenna (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 26; 129-136
    Format: text
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  • 3
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    Dynamic analysis and experiment methods for a generic space station model (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 24; 270-276
    Format: text
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  • 4
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    Correlation of ground tests and analyses of a dynamically scaled space station model configuration (1993)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Verification of analytical models through correlation with ground test results of a complex space truss structure is demonstrated. A multi-component, dynamically scaled space station model configuration is the focus structure for this work. Previously established test/analysis correlation procedures are used to develop improved component analytical models. Integrated system analytical models, consisting of updated component analytical models, are compared with modal test results to establish the accuracy of system-level dynamic predictions. Design sensitivity model updating methods are shown to be effective for providing improved component analytical models. Also, the effects of component model accuracy and interface modeling fidelity on the accuracy of integrated model predictions is examined.
    Keywords: STRUCTURAL MECHANICS
    Type: AIAA PAPER 93-1604 , In: AIAA(ASME)ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 34th and AIAA/ASME Adaptive Structures Forum, La Jolla, CA, Apr. 19-22, 1993, Technical Papers. Pt. 5 (A93-33876 1; p. 2612-2623.
    Format: text
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  • 5
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    Dynamic and thermal response finite element models of multi-body space structural configurations (1987)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Presented is structural dynamics modeling of two multibody space structural configurations. The first configuration is a generic space station model of a cylindrical habitation module, two solar array panels, radiator panel, and central connecting tube. The second is a 15-m hoop-column antenna. Discussed is the special joint elimination sequence used for these large finite element models, so that eigenvalues could be extracted. The generic space station model aided test configuration design and analysis/test data correlation. The model consisted of six finite element models, one of each substructure and one of all substructures as a system. Static analysis and tests at the substructure level fine-tuned the finite element models. The 15-m hoop-column antenna is a truss column and structural ring interconnected with tension stabilizing cables. To the cables, pretensioned mesh membrane elements were attached to form four parabolic shaped antennae, one per quadrant. Imposing thermal preloads in the cables and mesh elements produced pretension in the finite element model. Thermal preload variation in the 96 control cables was adjusted to maintain antenna shape within the required tolerance and to give pointing accuracy.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA-CR-178289 , NAS 1.26:178289
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  • 6
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    Quasi-static shape adjustment of a 15 meter diameter space antenna (1987)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A 15 meter diameter Hoop-Column antenna has been analyzed and tested to study shape adjustment of the reflector surface. The Hoop-Column antenna concept employs pretensioned cables and mesh to produce a paraboloidal reflector surface. Fabrication errors and thermal distortions may significantly reduce surface accuracy and consequently degrade electromagnetic performance. Thus, the ability to adjust the surface shape is desirable. The shape adjustment algorithm consisted of finite element and least squares error analyses to minimize the surface distortions. Experimental results verified the analysis. Application of the procedure resulted in a reduction of surface error by 38 percent. Quasi-static shape adjustment has the potential for on-orbit compensation for a variety of surface shape distortions.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: AIAA PAPER 87-0869
    Format: text
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  • 7
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    Correlation of ground tests and analyses of a dynamically scaled Space Station model configuration (1993)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Verification of analytical models through correlation with ground test results of a complex space truss structure is demonstrated. A multi-component, dynamically scaled space station model configuration is the focus structure for this work. Previously established test/analysis correlation procedures are used to develop improved component analytical models. Integrated system analytical models, consisting of updated component analytical models, are compared with modal test results to establish the accuracy of system-level dynamic predictions. Design sensitivity model updating methods are shown to be effective for providing improved component analytical models. Also, the effects of component model accuracy and interface modeling fidelity on the accuracy of integrated model predictions is examined.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA-TM-107729 , NAS 1.15:107729 , Structures, Structural Dynamics, and Materials Conference; Apr 19, 1993 - Apr 21, 1993; La Jolla, CA; United States
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  • 8
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    Status of DSMT research program (1991)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The status of the Dynamic Scale Model Technology (DSMT) research program is presented. DSMT is developing scale model technology for large space structures as part of the Control Structure Interaction (CSI) program at NASA Langley Research Center (LaRC). Under DSMT a hybrid-scale structural dynamics model of Space Station Freedom was developed. Space Station Freedom was selected as the focus structure for DSMT since the station represents the first opportunity to obtain flight data on a complex, three-dimensional space structure. Included is an overview of DSMT including the development of the space station scale model and the resulting hardware. Scaling technology was developed for this model to achieve a ground test article which existing test facilities can accommodate while employing realistically scaled hardware. The model was designed and fabricated by the Lockheed Missile and Space Co., and is assembled at LaRc for dynamic testing. Also, results from ground tests and analyses of the various model components are presented along with plans for future subassembly and matted model tests. Finally, utilization of the scale model for enhancing analysis verification of the full-scale space station is also considered.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA-TM-102764 , NAS 1.15:102764 , NASA/DoD CSI Conference; Nov 05, 1990 - Nov 07, 1990; Orlando, FL; United States
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