Roughness of crack interfaces in two-dimensional beam lattices - art. no. 125503

The roughness of crack interfaces is reported in quasistatic fracture, usin g an elastic network of beams with random breaking thresholds. For strong d isorders we obtain zeta = 0.86(3) for the roughness exponent, a result whic h is very different from the minimum energy surface exponent, i.e., zeta = 2/3. A crossover to lower values is observed as the disorder is reduced, th e exponent in this regime being strongly dependent on the disorder.