STATISTICAL-MODEL FOR SURFACE FRACTURE

We analyse the fracture dynamics of a thin film which covers an elasti c substrate subject to stretching. The system is modelled through its one-dimensional electrical analogue: a two-layer system (ladder networ k) with large conductors on one level and random fuses on the other. T he fragmentation process exhibits two different regimes, depending on whether the mean fragment size is large or small compared to an intrin sic correlation length. In the latter case we find a power law depende nce of the mean fragment size on the externally applied current, the e xponent depending on the distribution of the fuse strengths.