Scale Invariance of Fracture Surfaces in Ice
We present quantitative evidences for the self-affine, scale invariant character of tensile fracture surfaces in ice, based on the analysis of fracture profiles from laboratory tensile tests on S2 sea ice. The self-affine character of these fracture surfaces is revealed by a relationship between the statistics of the elevation measure (the “roughness”) and the scale of analysis, with a self-affine Hurst’s exponent close to 0.8. These lab-scale data are in striking agreement with some field measurements (Parsons 1993) at much larger scales on sea ice. So far, no definitive theoretical explanation of self-affinity of fracture surfaces has been proposed, though the role of material heterogeneities coupled with nonlocal correlations of the stress intensity factor along the crack front has been stressed. However, the necessary condition for a model of fracture propagation to create fractal fracture surface is the universal scaling of the mechanisms involved and a scale invariant fracture toughness. Therefore, the observed scale invariance of ice fracture surfaces argue for the scale invariance of the fracture process itself.
KeywordsFracture Surface Crack Front Scale Invariance Fracture Profile Universal Scaling
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