Universality and Hysteretic Dynamics in Rapid Fracture

A. Livne, G. Cohen, and J. Fineberg

The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel

(Received 14 March 2005; published 10 June 2005)

Experiments in the dynamic fracture of brittle polyacrylamide gels show that a single-crack state undergoes a hysteretic transition to the microbranching instability with a characteristic activation time. Quantitative measurements also indicate that features such as crack front inertia, self-focusing of microbranches, and the appearance of front waves are universal attributes of dynamic fracture.