COHESIVE ZONE MODELING OF DAMAGE AT THE TIP OF CRACKS IN SLENDER BEAMSTRUCTURES

The use of simple beam theory for cohesive zone modelling of the damag e response at the crack tip in linear elastic isotropic double cantile ver beam (DCB) specimens has been investigated. Damage resistance curv es (DR-curves) relating the applied stress intensity factor to the gro wth of the cohesive zones for beam theory modelling has been compared with two-dimensional elasticity calculations for different material pa rameters and specimen dimensions. A substantial difference is observed between DR-curves for the two types of models. As expected this diffe rence vanishes for decreasing beam heights. For large beam heights the DR-curves calculated by two-dimensional elasticity are approaching sm all-scale yielding DR-curves, i.e. DR-curves for an edge crack in an i nfinite plate. The beam height for which beam theory is applicable cou ld be up to 10(-3) times the height for which small scale bridging DR- curves are applicable.