Slow Crack Propagation in Heterogeneous Materials

Abstract

Statistics and thermally activated dynamics of crack nucleation and propagation in a two-dimensional heterogeneous material containing quenched randomly distributed defects are studied theoretically. Using the generalized Griffith criterion we derive the equation of motion for the crack tip position accounting for dissipation, thermal noise and the random forces arising from the defects. We find that aggregations of defects generating long-range interaction forces (e.g., clouds of dislocations) lead to anomalously slow creep of the crack tip or even to its complete arrest. We demonstrate that heterogeneous materials with frozen defects contain a large number of arrested microcracks and that their fracture toughness is enhanced to the experimentally accessible time scales.

5 pages, 1 figure

References in corpus (4)

• Acoustic Emission from Paper Fracture
• Creep in One Dimension and Phenomenological Theory of Glass Dynamics
• A New Criterion for Crack Formation in Disordered Materials
• Diffusion and Creep of a Particle in a Random Potential

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