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Structural Dynamic Analysis of a Spacecraft Multi-DOF Shaker TableFinite element enforced response analysis was performed on a multiple degree of freedom expander head shaker table to aid in the design of the table structure and vibration control system. The payload for this shaker system is a spacecraft with a multitude of flexible modes across a broad frequency band. A Craig-Bampton representation of the spacecraft was used to expedite analysis of multiple shaker table designs. The analysis examines the required forces in the actuators for a constant amplitude base acceleration sine sweep test, the resulting forces in the spacecraft and table attachment restraints, and the resulting accelerations on the spacecraft structure. The results show the spacecraft response at low frequencies is very high near the tip due to the low order spacecraft bending and axial modes. The high response can be addressed by notching the input vibration levels to avoid overtesting the spacecraft. At frequencies above 25 Hz, the spacecraft modal effective masses are very small, and the response of the shaker table dominates the response. Anti-resonances of the shaker table in the frequency range of interest reduce the acceleration output and require much higher actuator forces to achieve the acceleration specification. These effects may require stiffening the shaker structure to move the modes out of the test frequency range or increasing the shaker table damping.
Document ID
20090015864
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Pray, Carl
(ATA Engineering, Inc CA, United States)
Blelloch, Paul
(ATA Engineering, Inc CA, United States)
Thomas, Gareth
(ATA Engineering, Inc CA, United States)
McNelis, Mark
(NASA Glenn Research Center Cleveland, OH, United States)
Suarez, Vicente
(NASA Glenn Research Center Cleveland, OH, United States)
Otten, Kim
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 24, 2013
Publication Date
September 22, 2008
Publication Information
Publication: 25th Space Simulation Conference. Environmental Testing: The Earth-Space Connection
Subject Category
Space Sciences (General)
Distribution Limits
Public
Copyright
Public Use Permitted.

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