Physics of Cracking
Alain KARMA (Northeastern University)

Infos Complémentaires

Salle de Conférences IV - 24 rue Lhomond

2ème étage - 13h30

Jeudi 16 juin

Résumé :

Most engineering, biological, and geological materials ultimately fail under
large enough forces, as exemplified by catastrophic airplane failure, broken
bones, and earthquakes. Even though crack propagation is the most common
mode of failure, predicting the path of a crack in a material has remained a
major challenge. This challenge stems from the fact that cracking is controlled
by phenomena on multiple length and time scales from the elastic deformation
of the material on a macroscopic scale to the breaking of atomic bonds
on submicrometer to angstrom scales. I will present recent progress made
to understand how cracks propagate in a three-dimensional material through
computational and experimental studies. Computational studies exploit a new
class of fracture models that naturally bridge short and large scales of this
problem. The results shed light on the fundamental mechanism by which the
combination of tension and tearing leads to a widely observed and intriguing
fragmentation of a planar crack into multiple daughter crack segments or
”fracture lances”. They also highlight the need for a short-scale regularization
of standard crack propagation laws in three dimensions to avoid unphysical
ultraviolet divergences that have until recently escaped notice of the fracture
community.

Salle de Conférences IV - 24 rue Lhomond

2ème étage - 13h30