PhD thesis : "Transition from a nonlocal damage model to a cohesive zone model within the framework of quasi-brittle failure"

Sam Cuvilliez defend his PhD thesis on the subject "Transition from a nonlocal damage model to a cohesive zone model within the
framework of quasi-brittle failure
The" Wednesday, January 1st 2012 at 14:00, room L109, at l’École des Mines de Paris, 60 boulevard Saint-Michel, Paris.

Access à l’École des Mines de Paris

Abstract :
The present work deals with the study and the improvement of regularized (non local) damage models. It
aims to study the transition from a continuous damage field distributed on a structure to a discontinuous
macroscopic failure model.
First, an analytical one-dimensional study is carried out (on a bar submitted to tensile loading) in order to
identify a set of interface laws that enable to switch from an inhomogeneous solution obtained with a continuous
gradient damage model to a cohesive zone model. This continuous / discontinuous transition is constructed so
that the energetic equivalence between both models remains ensured whatever the damage level reached when
switching
This strategy is then extended to the bi-dimensional (and tri-dimensional) case of rectilinear (and plane)
crack propagation under mode I loading conditions, in a finite element framework. An explicit approach based on
a critical damage criterion that allows coupling both continuous and discontinuous approaches is then proposed.
Finally, results of several simulations led with this coupled approach are presented.

Keywords :
Nonlocal damage model, cohesive zone model, energetic equivalence, finite element method.