Cohesive-zone model identification using digital image correlation

Titre du congrès :PHOTOMECHANICS 2008 Ville du congrès :Loughborough Date du congrès :07/07/2008

Since a few years, cohesive-zone models have been formulated and used to simulate fracture of solid materials. The cohesive-zone models presented in the literature involve a 'jump' in the displacement field describing the crack onset within a predefined interface network which corresponds to interfaces between elements of the FE mesh. Nevertheless, the physical meaning of these displacement jumps is not obvious. Moreover, the forms of interface laws are often chosen in connection with the overall behavior and/or numerical considerations. In this study, we propose a simple onedimensional analysis where an additive decomposition of strain into plastic hardening and damage is used to build an interface law. Displacement data obtained by digital image correlation (DIC) from tensile tests are used to identify cohesivezone models for different materials. The proposed approach allows us to specify the physical sense of the usual forms of interface laws and the afore-mentioned displacement jumps introduced in the numerical simulations. Finally, we discuss the potentialities of DIC to assess the overall damage and its restriction to a surface damage in a cohesive-zone model.