Ponson, Laurent (2006) Failure of disordered materials: How to decipher fracture surfaces. PhD thesis SPCSI (CEA Saclay) et FAST (Orsay), SPCSI (CEA Saclay) et FAST (Orsay), EP/X p.133.
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Alternative Locations: http://www.imprimerie.polytechnique.fr/Theses/Files/Ponson.pdf
Abstract
For a half-century, engineers know how to describe and predict the propagation of a crack in a model elastic homogeneous medium. The case of real materials is much more complex. Indeed, we do not know how to relate their lifetime or their resistance to their microstructure. To achieve such a prediction, understanding the role of the microstructural disorder on the behavior of a crack is determinant. Fracture surfaces represent a promising field of investigation to address this question.
From the study of various disordered materials, we propose a statistical description of their roughness and determine to which extent their properties are dependent of the material. We show that fracture surfaces display an anisotropic scale invariant geometry characterized by two universal exponents. Glass ceramics is then studied because its microstructure can be tuned in a controlled manner. Their fracture surfaces display the same general anisotropic properties but with surprisingly low exponents independent of the detail of the ceramics microstructure. This suggests the existence of a second universality class in failure problems. Using finally theoretical tools from out-of-equilibrium statistical physics and fracture mechanics, we relate the statistical properties of fracture surfaces with the mechanisms occurring at the microscopic scale during the failure of a material. In particular, we show that the first class of fracture surfaces results from a failure involving !
damage processes while the second one results from a perfectly brittle failure.
| Item Type: | PhD Thesis (PhD) |
|---|---|
| Thesis Supervisor: | Hulin, Jean-Pierre |
| Date: | 24 November 2006 |
| Board of examiners: | Sergio, Ciliberto and Werner, Krauth and Itamar, Procaccia and Michel, Rosso and Stéphane, Roux |
| Ecole Doctorale: | ED 447 ECOLE DOCTORALE DE L'ECOLE POLYTECHNIQUE |
| Discipline: | SPCSI (CEA Saclay) et FAST (Orsay) |
| Collection (Fonds): | EP/X |
| Institution: | EP/X |
| Department: | SPCSI (CEA Saclay) et FAST (Orsay) |
| Subjects: | 3. Physics, Optics |
| Uncontrolled Keywords: | Fracture, Disordered materials, Roughness of fracture surfaces, Scaling invariance, Fracture mechanics, Elastic line in random medium, Rupture, Matériaux désordonnés, Rugosité des surfaces de rupture, Invariance d'échelle, Mécanique de la rupture, Ligne élastique en milieu aléatoire |
Table of content
1. Context and motivation
2. Morphology of fracture surfaces revisited
3. Low roughness exponents of fractured porous material surfaces
4. Fracture surfaces for model linear elastic disordered materials
| ID Code: | 2920 |
|---|---|
| Deposited By: | Laurence Vidament |
| Deposited On: | 06 September 2007 |
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