T-stress based fracture model for cracks in isotropic materials

• Published in: Engineering fracture mechanics 1998-07, Vol.60 (5), p.543-561
• Main Authors: Selvarathinam, A.S., Goree, J.G.
• Format: Article
• Language: English
• Subjects: branched-crack; dislocations; fracture; isotropic; T-stress
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/S0013-7944(98)00032-0

A modified version of the T-stress based fracture model, developed by Cotterell and Rice, is proposed. In this version an experimentally determined T crit value is included in the model. The model is then applied to a branched crack in an isotropic material, and the direction of growth of the crack is predicted qualitatively. The branched crack problem is solved using the method of dislocations and a singular integral equation is obtained. The singular integral equation is solved using three different numerical techniques and their respective merits are discussed. The stress intensity factors and the T-stress in front of the branched crack tip are evaluated numerically. It is shown that the T-stress and the stress intensity factors are insensitive to the order of the singularity assumed at the reentrant wedge corner of the branched crack. For an uniaxial load and short kink length it is demonstrated that the kink will turn from its initial direction and realign with the main crack. However if the loading is biaxial then the direction of kink growth depends strongly on the applied transverse stress σ xx . For a longer initial kink length the direction of kink growth depends on both the kink angle and loading.