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Dynamique de fracture d'un hydrogel thermoréversible de biopolymères

Abstract : In this work, we have studied the crack dynamics in a reversible hydrogel of biopolymers : the gelatin. Our fracture experiments, conducted in mode 1, in a quasi-stationary and subsonic regime shows that, contrary to chemical gels and elastomers, fracture propagation do not process by chains scissions : chains are pulled out the lattice at the crack head, and dissipation arise from the friction of chains with solvent. A simple Dugdale-type model gives the orders of magnitude and predicts the scaling laws experimentally observed.

We have also studied the surface morphologies resulting from the fracture of gelatin. Contrary to what is observed in brittle materials, they do not exist scaling laws but the roughness profiles present an RMS height which increase with crack propagation velocity, observation never reported before. We have measured an upper critical speed for the appearance of macroscopic defects, defects which have been observed by Gent et al. in elastomers and described in details by Sekimoto et al. in polyacrylamide gels. We explain the characteristic height of these defects by taking into account the blunting of the fracture head characteristic of soft solids. Also, these defects and the rugosity show an anisotropy along a magic angle independent of crack propagation speed and characteristics of gelatin gel.
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https://tel.archives-ouvertes.fr/tel-00329187
Contributor : Elisabeth Martin <>
Submitted on : Friday, October 10, 2008 - 2:47:04 PM
Last modification on : Thursday, December 10, 2020 - 10:50:33 AM
Long-term archiving on: : Monday, June 7, 2010 - 6:53:43 PM

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  • HAL Id : tel-00329187, version 1

Citation

David Martina. Dynamique de fracture d'un hydrogel thermoréversible de biopolymères. Analyse de données, Statistiques et Probabilités [physics.data-an]. Université Pierre et Marie Curie - Paris VI, 2008. Français. ⟨tel-00329187⟩

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