Intermittency and localization in compressive failure of heterogeneous materials
Event details
| Date | 31.03.2017 |
| Hour | 12:15 › 13:00 |
| Speaker | Dr Laurent Ponson, Institut Jean le Rond d’Alembert, UPMC – CNRS, Paris, France |
| Location | |
| Category | Conferences - Seminars |
Abstract:
Beyond some critical load, solids under traction break through the propagation of a crack. Under slowly increasing compressive load, the failure mode of materials turns out to be qualitatively different: They first damage rather homogeneously until the emergence of a thin localization band where most fracture mechanisms subsequently concentrates. The specimen then loses its ability to carry mechanical load through sliding along the newly created fault.
To predict localization and ensure the mechanical integrity of structures, current models build on damage mechanics that describe the evolution of damage in a continuum homogeneous medium. However, this approach relies on the ad hoc introduction of non-local effects that control the localization threshold and so the bearing load capacity. Moreover, these models overlook the central role played by the microstructural heterogeneities at the origin of the strong intermittent mechanical response observed prior localization and the size effects characterizing the failure behavior of materials under compression. During this seminar, I will address these challenges through the study of damage spreading and localization in heterogeneous solids. First, this will reveal the mechanism at the origin of the non-local behavior of damaging solids, namely the process of load redistribution taking place in elasto-damageable media after any single damage event. We will show how to use this process as a building block to predict localization, but also to rationalize the giant fluctuations observed during the phase of progressive damage preceding failure. Finally, I will show how this extension of damage mechanics to heterogeneous solids may be used to predict the emergent properties of quasi-brittle solids from their microstructural features. For pedagogical purposes, the theoretical concepts introduced during this seminar will be illustrated through experiments performed on model heterogeneous solids.
Short Bio:
Dr Laurent Ponson is chargé de Recherche CNRS at the Institut Jean Le Rond d’Alembert of the University Pierre & Marie Curie in Paris (Paris 6), France. Laurent graduated from Ecole Centrale in 2003 and obtained his PhD in Physics from Ecole Polytechnique, France in 2006. His research interests cover the topics of complexity in solid mechanics, fracture and damage mechanics as well as out-of-equilibrium statistical physics.
Beyond some critical load, solids under traction break through the propagation of a crack. Under slowly increasing compressive load, the failure mode of materials turns out to be qualitatively different: They first damage rather homogeneously until the emergence of a thin localization band where most fracture mechanisms subsequently concentrates. The specimen then loses its ability to carry mechanical load through sliding along the newly created fault.
To predict localization and ensure the mechanical integrity of structures, current models build on damage mechanics that describe the evolution of damage in a continuum homogeneous medium. However, this approach relies on the ad hoc introduction of non-local effects that control the localization threshold and so the bearing load capacity. Moreover, these models overlook the central role played by the microstructural heterogeneities at the origin of the strong intermittent mechanical response observed prior localization and the size effects characterizing the failure behavior of materials under compression. During this seminar, I will address these challenges through the study of damage spreading and localization in heterogeneous solids. First, this will reveal the mechanism at the origin of the non-local behavior of damaging solids, namely the process of load redistribution taking place in elasto-damageable media after any single damage event. We will show how to use this process as a building block to predict localization, but also to rationalize the giant fluctuations observed during the phase of progressive damage preceding failure. Finally, I will show how this extension of damage mechanics to heterogeneous solids may be used to predict the emergent properties of quasi-brittle solids from their microstructural features. For pedagogical purposes, the theoretical concepts introduced during this seminar will be illustrated through experiments performed on model heterogeneous solids.
Short Bio:
Dr Laurent Ponson is chargé de Recherche CNRS at the Institut Jean Le Rond d’Alembert of the University Pierre & Marie Curie in Paris (Paris 6), France. Laurent graduated from Ecole Centrale in 2003 and obtained his PhD in Physics from Ecole Polytechnique, France in 2006. His research interests cover the topics of complexity in solid mechanics, fracture and damage mechanics as well as out-of-equilibrium statistical physics.
Practical information
- General public
- Free
Organizer
- Katrin Beyer & Brice Lecampion
Contact
- Brice Lecampion