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