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Static and free-vibrational response of semi-circular graphite-epoxy frames with thin-walled open sectionsExperiments 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 formulation of the element is based on a Vlasov-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 than was observed in the experiments.
Document ID
19900004284
Document Type
Contractor Report (CR)
Authors
Collins, J. Scott (Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Johnson, Eric R. (Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1989
Subject Category
COMPOSITE MATERIALS
Report/Patent Number
VPI-E-89-19
CCMS-89-21
NASA-CR-186097
NAS 1.26:186097
Funding Number(s)
CONTRACT_GRANT: NAG1-343
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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