MICRO-BRANCHING AS AN INSTABILITY IN DYNAMIC FRACTURE
The proceedings of the IUTAM conference (
J. FINEBERG†, S. P. GROSS‡ AND
†The Racah Institute of Physics
‡The Center for Nonlinear Dynamics
Experiments in brittle, amorphous PMMA indicate that the process of dynamic fracture is governed by a micro-branching instability. At a critical velocity, vc, a single crack undergoes an abrupt, well-defined transition to microscopic crack branching. As a result, the velocity of the crack develops oscillations, the mean acceleration decreases and structure is formed on the fracture surface. Beyond vc the total fracture surface created is a linear function of the energy release rate. Micro-branch profiles follow a power law and develop into macroscopic crack branching.