MIXED-MODE FRACTURE-MECHANICS OF ANISOTROPIC PLATES BY MEANS OF THE T-CRITERION

A direct generalization of the T-criterion for the prediction of mixed-mode fracture characteristics of homogeneous anisotropic plates is given in this paper. This fracture criterion, introduced by one of the authors (P.S.T), was successfully used in various LEFM applications with isotropic materials as well as for cases where small scale yielding (s.s.y) of metallic materials was encountered. Due to the principles of T-criterion, according to which the different role played by the distortional and dilatational strain-energy density in fracture is fully recognized, its eventual use with anisotropic materials was prohibited, since the decomposition of the anisotropic elastic potential was not as yet conceivable. It is in terms of such an analytical decomposition especially for transversely isotropic media, recently derived by the authors, that the present generalization of the T-criterion was undertaken. Although the example problems treated herein assume homogeneously anisotropic media, preliminary comparison of the theoretical predictions with experimental data from fibrous composites revealed satisfactory agreement.