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DY: Dynamik und Statistische Physik

DY 25: Growth and Roughness

DY 25.5: Talk

Tuesday, March 9, 2004, 16:00–16:15, H3

Fast Crack Growth by Surface Diffusion — •Robert Spatschek and Efim Brener — Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich

Fracture is an intriguing irreversible phenomenon that plays an important role in our day-to-day-life. Crack propagation is responsible for the vast field of material failure but is also an interesting subject of physical research. In particular, it exhibits several peculiarities for higher propagation velocities. Here we present a continuum theory which describes the fast growth of a crack by surface diffusion. By introducing a fully dynamical theory of elasticity, it is possible to obtain a self-consistent selection of the crack tip radius. This theory describes the complicated dynamics of a crack tip, the saturation of the steady state velocity appreciably below the Rayleigh speed, and the blunting of the crack tip. Furthermore, it includes the possibility of a tip splitting instability for high applied tensions.