Font Size: 

The presence of complex terms in the Williams’ asymptotic expansion ofthe near tip field of an interface crack makes the analysis of the crack propagation moreintricate. Griffith’s criterion remains valid for the delamination growth because in thisparticular case the energy release rate does not involve oscillating terms. This is nolonger true if the crack kinks out of the interface. Due to the oscillating terms, theenergy release rate is ill-defined and it becomes impossible to extend Grifitth’scriterion. Taking the T-stress, i.e. the next term of the asymptotic expansion, intoaccount allows getting rid of this difficulty thanks to a characteristic length derivedfrom a two-fold criterion using both energy and stress conditions.