Damage at heterogeneous interfaces

We discuss the progressive damage of an heterogeneous interface modelled through a fiber bundle with random strength, coupled to two semi-infinite elastic blocks. We show that a hierarchical description of the elastic blocks and an homogeneous damageable interface gives rise to a cascade of bifurcations associated to the progressive concentration of damage activity of a narrower and narrower domain starting from half the system size. The disorder in the limit of an infinite size of the elastic block is a weak relevance for the global effective interface law.