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<p>This dissertation explores the stability of beams, plates and membranes due to
subsonic aerodynamic flows or solar radiation forces. Beams, plates and membranes
are simple structures that may act as building blocks for more complex systems. In
this dissertation we explore the stability of these simple structures so that one
can predict instabilities in more complex structures. The theoretical models include
both linear and nonlinear energy based models for the structural dynamics of the featureless
rectangular structures. The structural models are coupled to a vortex lattice model
for subsonic fluid flows or an optical reflection model for solar radiation forces.
Combinations of these theoretical models are used to analyze the dynamics and stability
of aeroelastic and solarelastic systems. The dissertation contains aeroelastic analysis
of a cantilevered beam and a plate / membrane system with multiple boundary conditions.
The dissertation includes analysis of the transition from flag-like to wing-like flutter
for a cantilevered beam and experiments to quantify the post flutter fluid and structure
response of the flapping flag. For the plate / membrane analysis, we show that the
boundary conditions in the flow direction determine the type of instability for the
system while the complete set of boundary conditions is required to accurately predict
the flutter velocity and frequency. The dissertation also contains analysis of solarelastic
stability of membranes for solar sail applications. For a fully restrained membrane
we show that a flutter instability is possible, however the post flutter response
amplitude is small. The dissertation also includes analysis of a membrane hanging
in gravity. This systems is an analog to a spinning solar sail and is used to validate
the structural dynamics of thin membranes on earth. A linear beam structural model
is able to accurately capture the natural frequencies and mode shapes. Finally, the
dissertation explores the stability of a spinning membrane. The analysis shows that
a nonlinear model is needed to produce a conservative estimate of the stability boundary.</p>
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