Problem: Analyze vibration performance of a complex
prototype structure using sub-system models provided by
multiple
contractors. |
Integrated Modeling
SDL is
currently under contract to the U.S. Air Force Research Laboratory (AFRL) to
provide integrated modeling and vibration analysis for a prototype deployable
space telescope (DST). The figure to the right shows the major DST subsystems
in different colors, each being manufactured by different contractors. The
integrated modeling effort involves assembling the individual subsystem
finite-element models provided by the contractors into a single system-level
finite-element model. |
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AFRL Prototype Deployable Space
Telescope
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Base Excitation Power Spectral Density
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Substructuring
SDL uses powerful sub-structuring techniques which enable the merging of modal models obtained from either experimental or finite-element modeling. The use of experimental modal models can significantly increase the fidelity of the overall system model. Sub-structuring also allows easy comparison of subsystem designs. |
PSD Analysis
The purpose of the vibration analysis is to verify subsystem as well as system-level performance. Prior to fabrication, this information is used to evaluate subsystem designs, after fabrication, this information will be used to assess the need for modifications during system integration. By using power spectral density (PSD) curves for the disturbances expected during system operation, along with frequency response functions describing the system's input-output behavior, PSD's of important system responses may be computed. The integral of the PSD represents the mean-square value of the corresponding time response.
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Typical Frequency Response Function
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