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Designers of SOFIA airborne telescope see
results with COSMOS software
Company
NASA and the
German Aerospace Center (DLR) |
Industry
Aerospace/Defense |
Location
U.S.A. |
Product Used
COSMOSM
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Type of Analysis
Linear Static,
Frequency, Displacement Analysis |
More Details
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The SOFIA telescope will sit in a bay exposed
to stratospheric conditions while users control
it from the pressurized cabin of a Boeing 747SP
aircraft. |
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The Challenge
Designing a key piece of the SOFIA (Stratospheric Observatory
for Infrared Astronomy) project, which will mount a 2.5-meter
telescope on a 747 jet liner, does more than offer scientists
better views of space from the Earth. It also underscores the
growing role that finite element analysis (FEA) software plays
in aerospace design, with resulting gains in cost, time, and quality.
A seven-person team,
headed by Edward Dunham, at the Lowell Observatory in Flagstaff,
Arizona, designed and built the HIPO (High-speed Imaging Photometer
for Occultations), which will be used in the initial SOFIA test
program as well as for subsequent scientific observation. The
800-pound HIPO instrument will serve as a camera to capture images
viewed through the telescope.
Specific objectives
were to:
- predict the displacements (as related to 33 load cases) and
the six lowest free-vibration natural frequencies for the initial
design of the HIPO instrument;
- evaluate the predicted performance of the HIPO instrument
as related to meeting the structural design objectives; and
- provide appropriate redesign recommendations if necessary.
The Solution
Using the COSMOSM Finite Element System software, Loverich generated
and analyzed the finite element model of the HIPO instrument. Analysis
determined that the original configuration finite element model
of the HIPO Instrument did not meet the structural design objectives
involving natural frequencies. Subsequent to numerous model trial
modifications and finite element analysis iterations, various structural
enhancements were made to the original model in order that the structural
design objectives involving natural frequencies, displacements,
and structure weight would be optimally and satisfactorily met.
These structural modifications (involving increased plate thickness
dimensions, structure additions, and structure component rearrangement)
were included in the redesign finite element model and the associated
model versions of the HIPO Instrument.
Summary and Metrics:
- Determined that original configuration of the HIPO instruments
did not meet structural design objectives involving natural
frequencies
- Allowed major prototyping that would otherwise have been impossible
due to the prohibitive cost and time involved.
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