Title:
Photogrammetry Analysis of a Hypersonic Inflatable
Aerodynamic Decelerator Structural Test Article
Photogrammetry Analysis of a Hypersonic Inflatable
Aerodynamic Decelerator Structural Test Article
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Author(s)
Li, Lin
Advisor(s)
Braun, Robert D.
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Abstract
Analysis was performed on photogrammetry data of a 6m Hypersonic Inflatable
Aerodynamic Decelerator (HIAD), an inflatable stacked torus used to aid in atmospheric
entry, to understand its structural dynamics. Photogrammetry data was obtained during
wind tunnel testing under various loading conditions. Test parameters included the
freestream dynamic pressure, yaw angle and internal inflation pressure. In addition, two
HIAD configurations were analyzed, the basic stacked torus (Baseline configuration) and a
second configuration adding a torus near the shoulder to aid in rigidity (Tri-Tori
configuration). The analysis includes estimating the deflection of the HIAD under loading as
well as calculating the standard deviation relative to the mean deflection and the frequency
content of the dynamic response. Under load, the deflection angle for each configuration
ranged from 1° to 3° (1σ). Analysis of the results indicates that the Tri-Tori configuration
did not demonstrate significant benefit over the Baseline. The photogrammetry data showed
that the oscillatory motion increased with higher dynamic pressure but was insensitive to
yaw angle. In addition, the analysis showed that the standard deviation of the HIAD shape
with respect to the average deflection increased while moving radially outwards. However,
the standard deviation values calculated from different camera pairs were inconsistent and
did not produce the same standard deviations especially at the interface region. The
frequency analysis showed that each radial member behaved similarly to a rigid oscillator,
having the same frequency content of motion along each radial direction and increased
amplitude when moving radially outward. Both the frequency and shape standard deviation
analyses showed that the motion of the HIAD was piecewise continuous in the azimuthal
direction. These discontinuities likely arose when stitching together the images from
different camera pairs. The photogrammetry data is a valuable dataset providing insight
into the static and dynamic response of the HIAD under loading. However, inconsistencies in
the camera imaging and stitching need to be resolved and higher temporal resolution will
improve the fidelity of analysis
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Date Issued
2013-07-11
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Resource Type
Text
Resource Subtype
Masters Project
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