Materials Transactions, JIM
Online ISSN : 2432-471X
Print ISSN : 0916-1821
ISSN-L : 0916-1821
Criterion for Combined Mode I-II Brittle Fracture
Hideo AwajiToshiya Kato
Author information
JOURNAL FREE ACCESS

1999 Volume 40 Issue 9 Pages 972-979

Details
Abstract

The Griffith concept of energy equilibrium for brittle mode I crack propagation was extended to mode II and combined mode I-II crack extensions. First, the maximum energy release rate for an infinitesimally kinked crack extension under combined mode I-II loading analyzed by Kageyama and Okamura was successfully expressed by a combined mode stress intensity factor. Second, the ratio between mode I and mode II fracture energy rates was estimated from the areas of the frontal process zone estimated from the area enclosed in the iso-stress contours of both the maximum principal stress and the maximum shear stress. Third, those considerations led to a predicted KIICKIC ratio of 1.20, which was quite near the experimental results of 1.1 to 1.3 obtained earlier. Finally, the combined mode I-II fracture criterion was formulated by the same technique, and the predicted criterion coincided well with Singh and Shetty’s empirical criterion.
The fracture toughness values of modes I and II, and the combined mode I-II criterion for polycrystalline alumina were also estimated experimentally using a disk method. The estimated result of KIICKIC ratio was 1.17, which was very close to the predicted value of 1.20. The experimentally assessed combined mode fracture criterion was closely related to the predicted one.

Content from these authors
© The Japan Institute of Metals
Previous article Next article
feedback
Top