TRICRITICAL BEHAVIOR IN RUPTURE INDUCED BY DISORDER

We discover a qualitatively new behavior for systems where the load tr ansfer has limiting stress amplification as in real fiber composites. We find that the disorder is a relevant field leading to tricriticalit y, separating a first-order regime where rupture occurs without signif icant precursors from a second-order regime where the macroscopic elas tic coefficient exhibits power law behavior. Our results are based on analytical analysis of fiber bundle models and numerical simulations o f a two-dimensional tensorial spring-block system in which stick-slip motion and fracture compete.