Defect nucleation modelling

International audienceThe purpose of this article is to compare concepts of defect nucleation based onbifurcation of equilibrium solution and on damage modelling. The nucleation criterionis defined as a bifurcation of the equilibrium solutions of the perfect body and of theimperfect one when the size of the defect vanishes. The defect is considered as a smallvolume which evolves as a damaged zone. To study the inuence of geometry of thedefect on the critical loading governing its initiation, we consider the particular cases ofa linear elastic composite sphere and of a linear elastic composite cylinder, for which theequilibrium solutions are known when the radial distribution of elastic bulk modulus isgiven simultaneously with an uniform shear modulus. The initial defect is a small sphereor a small cylinder respectively, it can be a cavity or a kernel made with an elasticmaterial with lower mechanical properties