SYMPOSIA PAPER Published: 01 January 1985

Crack Tip Plasticity of a Tearing Crack


The effects of crack tip plasticity associated with rapid tearing under Mode I and stable crack growth under combined Modes I and II crack tip deformations are analyzed by a modified Dugdale model. The modification consists of an unloaded region immediately ahead of the crack tip. The wake of the extending crack is modeled by two equal and unequal tangential surface tractions acting at the crack tip for Mode I and combined Modes I and II loadings, respectively. The disposable parameters plus the higher order terms in the crack tip stress field associated with the modified Dugdale model are then determined by using the dynamic photoelasticity results of rapid tear and stable crack growth in thin polycarbonate sheets. The modified Dugdale model is justified by the good agreement between the computed and directly measured isochromatics. Crack tip opening displacement (CTOD) and crack tip opening angle (CTOA) obtained from the least-square fitted, modified Dugdale model remained nearly constant during ductile crack extension.

Author Information

Lee, OS
University of Washington, Seattle, WA Inha University, Inchon, Korea
Kobayashi, AS
University of Washington, Seattle, WA
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Developed by Committee: E08
Pages: 431–450
DOI: 10.1520/STP34267S
ISBN-EB: 978-0-8031-4933-5
ISBN-13: 978-0-8031-0225-5