Defect nucleation modelling
Résumé
The purpose of this article is to compare concepts of defect nucleation based on
bifurcation of equilibrium solution and on damage modelling. The nucleation criterion
is defined as a bifurcation of the equilibrium solutions of the perfect body and of the
imperfect one when the size of the defect vanishes. The defect is considered as a small
volume which evolves as a damaged zone. To study the in
uence of geometry of the
defect on the critical loading governing its initiation, we consider the particular cases of
a linear elastic composite sphere and of a linear elastic composite cylinder, for which the
equilibrium solutions are known when the radial distribution of elastic bulk modulus is
given simultaneously with an uniform shear modulus. The initial defect is a small sphere
or a small cylinder respectively, it can be a cavity or a kernel made with an elastic
material with lower mechanical properties.