Journal Published Online: 01 December 1988
Volume 10, Issue 4

Strain Energy Release Rate Analysis of the End-Notched Flexure Specimen Using the Finite-Element Method



Two-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 GII. The GII 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-semispan (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 GII values calculated using the compliance derivative method compared extremely well with those calculated using the virtual crack-closure technique. The GII 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 GII values for one material system calculated from the finite-element analysis agreed with one solution in the literature and disagreed with the other solution in the literature.

Author Information

Salpekar, SA
Analytical Services and Materials, Inc., Hampton, VA
Raju, IS
Analytical Services and Materials, Inc., Hampton, VA
O'Brien, TK
Aerostructures Directorate, U.S. Army Aviation Research and Technology Activity (AVSCOM), NASA Langley Research Center, Hampton, VA
Pages: 7
Price: $25.00
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Stock #: CTR10275J
ISSN: 0884-6804
DOI: 10.1520/CTR10275J