Regensburg 2007 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 1: Internal Symposium: Physics of fracture

DY 1.6: Talk

Monday, March 26, 2007, 11:45–12:00, H2

Minimal Phase-Field Modeling For Fast Crack Propagation — •Clemens Müller-Gugenberger, Robert Spatschek, and Efim Brener — Institut für Festkörperforschung, Forschungszentrum 52425 Jülich

Usually, fracture is understood at the microscopic level by the breaking of bonds between atoms at sharp crack tips. However, in many materials, one observes rounded crack tips and a macroscopic description becomes possible. Such a description should not only determine the crack speed but also the crack shape self-consistently.

We developed a minimal model in the framework of a continuum theory of pattern formation. It is based on the Grinfeld instability and overcomes the usual finite time cusp singularity by incorporating elastodynamic effects which restore the selection of the steady state tip radius and velocity. The phase-field method is particularily suited for solving this moving free boundary problem.

We show that with large-scale computations, the quantitative results of this fully dynamical approach can be compared to approaches based on sharp-interface steady-state methods. The model encompasses many generic features of crack growth such as a tip speed well below the Rayleigh speed and tip splitting for high applied tension.