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A preliminary investigation of finite-element modeling for composite rotor bladesThe results from an initial phase of an in-house study aimed at improving the dynamic and aerodynamic characteristics of composite rotor blades through the use of elastic couplings are presented. Large degree of freedom shell finite element models of an extension twist coupled composite tube were developed and analyzed using MSC/NASTRAN. An analysis employing a simplified beam finite element representation of the specimen with the equivalent engineering stiffness was additionally performed. Results from the shell finite element normal modes and frequency analysis were compared to those obtained experimentally, showing an agreement within 13 percent. There was appreciable degradation in the frequency prediction for the torsional mode, which is elastically coupled. This was due to the absence of off-diagonal coupling terms in the formulation of the equivalent engineering stiffness. Parametric studies of frequency variation due to small changes in ply orientation angle and ply thickness were also performed. Results showed linear frequency variations less than 2 percent per 1 degree variation in the ply orientation angle, and 1 percent per 0.0001 inch variation in the ply thickness.
Document ID
Document Type
Conference Paper
Lake, Renee C.
(NASA Langley Research Center Hampton, VA, United States)
Nixon, Mark W.
(NASA Langley Research Center; U.S. Army, Aerostructures Directorate, Hampton VA, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1988
Subject Category
Structural Mechanics
Meeting Information
International Conference on Rotorcraft Basic Research(College Park, MD)
Accession Number
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