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Effects of warping and pretwist on torsional vibration of rotating beams
Author and Affiliation:
Kaza, K. R. V.(NASA Lewis Research Center, Cleveland, OH, United States);
Kielb, R. E.(NASA Lewis Research Center, Cleveland, OH, United States)
Abstract: The effect of pretwist and warping on the torsional vibration of short-aspect-ratio rotating beams is examined for application to the modeling of turbofan, turboprop, and compressor blades. The equations of motion and the associated boundary conditions by using both Wagner's hypothesis and Washizu's theory are derived and a few minor limitations of the Wagner's hypothesis, as applied to thick blades, are pointed out and discussed. The equations for several special cases are solved in a closed form. Results are presented indicating the effect of warping, pretwist, and rotation on torsional vibration of beams as aspect ratio is varied. The results show that the structural warping and pretwist terms have a significant effect on torsional frequency and mode shapes of short-aspect-ratio blades whereas the inertial warping terms have negligible effect. Since the torsional frequencies and mode shapes are very important in aeroelastic analyses by using modal methods, the structural warping terms should be included in modeling turbofan, turboprop, compressor, and turbine blades.
Publication Date: Dec 01, 1984
Document ID:
19850034889
(Acquired Nov 28, 1995)
Accession Number: 85A17040
Subject Category: STRUCTURAL MECHANICS
Report/Patent Number: ASME PAPER 84-WA/APM-41
Document Type: Journal Article
Publication Information: ASME, Transactions, Journal of Applied Mechanics (ISSN 0021-8936); 51; 913-920
Publisher Information: United States
Financial Sponsor: NASA; United States
Organization Source: NASA Lewis Research Center; Cleveland, OH, United States
Description: 8p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: BEAMS (SUPPORTS); DYNAMIC STRUCTURAL ANALYSIS; PRESTRESSING; ROTATING BODIES; TORSIONAL VIBRATION; EQUATIONS OF MOTION; SLENDER BODIES; TURBINE BLADES; TWISTING
Imprint And Other Notes: (American Society of Mechanical Engineers, Winter Annual Meeting, New Orleans, LA, Dec. 9-14, 1984) ASME, Transactions, Journal of Applied Mechanics (ISSN 0021-8936), vol. 51, Dec. 1984, p. 913-920.
Availability Source: Other Sources
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