Fracture roughness scaling: A case study on planar cracks

¹ Laboratoire de Physique, UMR CNRS 5672, Ecole Normale Supérieure de Lyon 46 allée d'Italie, F-69007 Lyon, France, EU
² Physics of Geological Processes, Oslo University - 1048 Blindern, N-0316 Oslo, Norway
³ Fysisk Institutt, Universitetet i Oslo - 1048 Blindern, N-0316 Oslo, Norway
⁴ Institut de Physique du Globe de Strasbourg, UMR CNRS 7516, EOST/Université de Strasbourg 5 rue René Descartes, F-67084 Strasbourg Cedex, France, EU
⁵ Institutt for fysikk, Norges teknisk-naturvitenskapelige Universitet - N-7491 Trondheim, Norway

^a stephane.santucci@ens-lyon.fr

Received: 13 October 2010
Accepted: 2 November 2010

Abstract

Using a multi-resolution technique, we analyze large in-plane fracture fronts moving slowly between two sintered Plexiglas plates. We find that the roughness of the front exhibits two distinct regimes separated by a crossover length scale δ^*. Below δ^*, we observe a multi-affine regime and the measured roughness exponent ζ_∥⁻=0.60±0.05 is in agreement with the coalescence model. Above δ^*, the fronts are mono-affine, characterized by a roughness exponent ζ_∥⁺=0.35±0.05, consistent with the fluctuating line model. We relate the crossover length scale to fluctuations in fracture toughness and the stress intensity factor.