• 1 Conservatoire National des Arts et Métiers [CNAM]

At the interface between two media with different wave velocities, local stationary waves can appear. The mechanical explanation is that the reflection of the waves is more important inwards the softest media. The overstressing which appears at the interface between the two media can be at the origin of a damage mechanism. Our goal is to suggest an energetical method in order to be able to compute accurately the energy release rate due to this overstressing without being obliged to use a very refined mesh in the neighbourhood of the interface.