CSAR Seminar
SPEAKER: Katerina Papoulia, Cornell University
TITLE:
Cohesive Fracture: Algorithms and Models
DATE: Tuesday, May 9, 2006
TIME: 12:00 Noon
PLACE: 2240 DCL
1304 W. Springfield Ave., Urbana, IL
ABSTRACT
Introduced by Barenblatt and Dugdale in the 1960's, cohesive fracture
postulates that cracks grow because a material's inherent ability to
self-cohere degrades when sufficiently high loads are applied at crack
sites. In the area of dynamic fracture, we have analyzed adaptive
finite element models of cohesive fracture, which are applicable to the
case of crack growth in a homogeneous material in which the crack may
follow complicated patterns not known in advance. We have shown that
finite element analysis is unlikely to converge to any kind of
underlying mechanical solution unless the model has a property called
time continuity and the spatial discretization is sufficiently rich in
element orientations, a condition known to be satisfied by a single
class of discretizations (pinwheel meshes). We have also applied
cohesive fracture to the prediction of fatigue crack growth by showing
that cohesive fracture in this area can be equated to introduction of a
damage variable whose evolution describes stiffness degradation as well
as crack healing via closure.
Parts of this talk represent joint work with A. Ural, C. Sam, P. Ganguly,
V. Krishnan, and S. Vavasis.