SYMPOSIA PAPER Published: 01 January 1983
STP36791S

Thickness Effects on the Choice of Fracture Criteria

Source

The stresses and strains in a cracked solid are in a complicated three-dimensional state. There are three two-dimensional limiting cases: plane strain, plane stress, and Dugdale's strip yielding case. The thickness of a plate relative to crack tip plastic zone size determines which one of these three limiting cases is predominant. The characteristics of the plane-stress and the Dugdale strip yielding crack-tip fields were investigated with the moire method together with the finite-element calculations. The state of the crack-tip stress and strain fields approaches that of plane strain for very thick plates. For a very thin plate with a very large crack-tip plastic zone, the Dugdale strip yielding model is applicable, and the crack opening displacement, crack-tip opening displacement, and thickness contraction are related to K or J and they can be used for fracture toughness measurements. When a plate thickness is in between these two extremes, there exists a characteristic plane stress crack-tip field. The correspondence of the planestress crack-tip fields in small-scale yielding and in general yielding was established, and the J value of a small specimen in general yielding can be obtained from the established correspondence. The value of the applied J-field of a small specimen in general yielding can be measured in terms of the applied stress and the specimen elongation.

Author Information

Liu, HW
Syracuse University, Syracuse, N.Y.
Hu, W
Hanford Engineering Development Laboratory, Westinghouse Corp.
Kuo, AS
Fairchild Republic Co.
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Details
Developed by Committee: E08
Pages: 632–656
DOI: 10.1520/STP36791S
ISBN-EB: 978-0-8031-4870-3
ISBN-13: 978-0-8031-0726-7