TRAJECTORIES OF UNSTABLY GROWING CRACKS IN MIXED-MODE I-II LOADING OFMARBLE BEAMS

Citation
Gs. Xeidakis et al., TRAJECTORIES OF UNSTABLY GROWING CRACKS IN MIXED-MODE I-II LOADING OFMARBLE BEAMS, Rock mechanics and rock engineering, 30(1), 1997, pp. 19-33
Citations number
15
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geosciences, Interdisciplinary","Engineering, Civil
ISSN journal
0723-2632
Volume
30
Issue
1
Year of publication
1997
Pages
19 - 33
Database
ISI
SICI code
0723-2632(1997)30:1<19:TOUGCI>2.0.ZU;2-5
Abstract
The knowledge of the stress field under which a crack in an engineerin g material or a rock is propagated and the trajectory it follows durin g its growth, is very important. In this paper the prediction of the c rack growth trajectory and its initial angle theta(c) under mixed mode I-II loading is studied experimentally in marble beams. The three poi nt bending test is used, together with the strain energy density theor y (SED) of Linear Elastic Fracture Mechanics (LEFM). Experimental resu lts are compared with theoretical predictions. The experimental result s showed that: marble behaved as a brittle material; crack propagation was unstable and its trajectory followed, mainly, the grain boundarie s; the prediction of the critical angle theta(c) and the first part of the trajectory, from the crack tip up to the point G, where a global minimum of the strain energy density is reached, can satisfactorily be made with the SED theory. Beyond point G, the initial stress field is different, and for application of the SED theory, the boundary condit ions need redefinition.