MODIFICATION OF THE G-CRITERION FOR CRACK-PROPAGATION SUBJECTED TO COMPRESSION

Citation
B. Shen et O. Stephansson, MODIFICATION OF THE G-CRITERION FOR CRACK-PROPAGATION SUBJECTED TO COMPRESSION, Engineering fracture mechanics, 47(2), 1994, pp. 177-189
Citations number
17
Categorie Soggetti
Mechanics
ISSN journal
00137944
Volume
47
Issue
2
Year of publication
1994
Pages
177 - 189
Database
ISI
SICI code
0013-7944(1994)47:2<177:MOTGFC>2.0.ZU;2-L
Abstract
Brittle materials subjected to compression can fail and the resulting cracks can propagate in mode I and mode II in two dimensions. The maxi mum strain energy release rate criterion (G-criterion) is examined for its capacity of predicting the mixed mode crack propagation. When thi s criterion is applied to an inclined crack subjected to compression, it predicts the shear failure but not the tensile failure. The reason for this phenomenon is discussed and a new form of this criterion, nam ely the F-criterion, is proposed. The F-criterion uses the sum of norm alized G(I) and G(II) (F = G(I)/G(Ic) + G(II)/G(IIc)) as the factor wh ich represents the crack propagation and its direction. Implemented in to the numerical displacement discontinuity method (DDM), the F-criter ion can predict both mode I and mode II propagation of a crack system. The capacity of the F-criterion in predicting both mode I and mode II propagation is demonstrated for two models subjected to uniaxial comp ression for a single crack and a set of two cracks. The numerical simu lations show good agreement with the results of laboratory experiments conducted on rocks and gypsum.