The 9th International Conference on Multiscale Materials Modeling

Presentation information

Symposium

K. Multiscale Simulations of Catastrophic Phenomena: Toward Bridging between Materials Fracture and Earthquake

[SY-K2] Symposium K-2

Thu. Nov 1, 2018 2:00 PM - 3:30 PM Room5

Chairs: Ferenc Kun(University of Debrecen, Hungary), Ian Main(University of Edinburgh, UK)

[SY-K2] Deciphering the dynamics of precursors to failure in quasi-brittle solids: an inspiration for understanding the statistics of earthquakes ?

Laurent Ponson1, Estelle Berthier1, Vincent Démery2 (1.Institut Jean le Rond d'Alembert, CNRS - Sorbonne University, Paris, France, 2.Gulliver, CNRS - ESPCI, Paris, France)

Quasi-brittle failure results from the evolution of a large number of interacting microcracks growing through the material microstructural disorder. Despite this complexity, quasi-brittle materials under slowly increasing compressive load exhibit a remarkably robust failure behavior: During a first stage, damage grows and accumulates through bursts of failure events that are localized both in space and time. This earthquake-like dynamic is characterized by scale free statistics with exponents that vary weakly with the type of materials and the loading conditions. Ultimately, the damage localizes into a macroscopic band that leads to the catastrophic failure of the specimen.
In this study, we investigate theoretically the physical mechanisms underlying intermittency and localization during quasi-brittle failure. Elasticity is shown to promote long-range interactions between the damaging elements constituting the specimen and to drive the collective response of the array of microcracks. To capture this cooperative dynamic, we encapsulate the interactions in an elastic kernel that derives from the continuum mechanics of elasto-damageable solids. We then show how it can be used to (i) disentangle the statistical properties of precursors to failure and explain their scale-free statistics and (ii) predict the onset of localization and the emerging fracture pattern. Our theoretical predictions are critically compared to experimental and numerical observations made during the compressive failure of disordered quasi-brittle solids.
The relevance of this theoretical framework for unravelling the statistics of earthquakes is finally discussed.