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Strain energy release rate analysis of the end-notched flexure specimen using the finite-element methodTwo-dimensional finite-element analysis of the end-notched flexure specimen was performed using 8-node isoparametric, parabolic elements to evaluate compliance and mode II strain energy release rates, G sub II. The G sub II values were computed using two different techniques: the virtual crack-closure technique (VCCT) and the rate of change of compliance with crack length (compliance derivative method). The analysis was performed for various crack-length-to-semi-span (a/L) ratios ranging from 0.2 to 0.9. Three material systems representing a wide range of material properties were analyzed. The compliance and strain energy release rates of the specimen calculated with the present finite-element analysis agree very well with beam theory equations including transverse shear. The G sub II values calculated using the compliance derivative method compared extremely well with those calculated using the VCCT. The G sub II values obtained by the compliance derivative method using the top or bottom beam deflections agreed closely with each other. The strain energy release rates from a plane-stress analysis were higher than the plane-strain values by only a small percentage, indicating that either assumption may be used in the analysis. The G sub II values for one material system calculated from the finte-element analysis agreed with one solution in the literature and disagreed with the other solution in the literature.
Document ID
19890038958
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Salpekar, S. A.
(Analytical Services and Materials, Inc. Hampton, VA, United States)
Raju, I. S.
(Analytical Services and Materials, Inc. Hampton, VA, United States)
O'Brien, T. K.
(NASA Langley Research Center; U.S. Army, Aerostructures Directorate, Hampton VA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1988
Publication Information
Publication: Journal of Composites Technology and Research
Volume: 10
ISSN: 0885-6804
Subject Category
Structural Mechanics
Accession Number
89A26329
Funding Number(s)
CONTRACT_GRANT: NAS1-18256
Distribution Limits
Public
Copyright
Other

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