Title page for ETD etd-02062013-040146
|Type of Document
||Collins, J. Scott
||Static and free-vibrational response of semi-circular graphite- epoxy frames with thin-walled open sections
||Master of Science
||Aerospace and Ocean Engineering
|Johnson, Eric R.
|Griffin, Odis Hayden Jr.
|Hyer, Michael W.
|Kapania, Rakesh K.
|Date of Defense
Experiments were conducted to measure the three-dimensional static and free
vibrational response of two graphite-epoxy, thin-walled, open section frames. The frames
are semi-circular with a radius of three feet, and one specimen has an I cross section and
the other has a channel cross section. The flexibility influence coefficients were measured
in static tests for loads applied at midspan with the ends of the specimens clamped.
Natural frequencies and modes were determined from vibrational tests for free and clamped end conditions. The experimental data is used to evaluate a new finite element which was developed specifically for the analysis of curved, thin-walled structures. The formulatio of the element is based on a Vlaysov-type, thin-walled, curved beam theory.
The predictions from the finite element program generally correlated well with the
experimental data for the symmetric I-specimen. Discrepancies in some of the data were
found to be due to flexibility in the ’clamped' end conditions. With respect to the data for the channel specimen, the correlation was less satisfactory. The finite element analysis
predicted the out-of-plane response of the channel specimen reasonably well, but
large discrepancies occurred between the predicted in-plane response and the experimental
data. The analysis predicted a much more compliant in-plane response then was
observed in the experiments.
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