A Modeling Study of the Effect of Stress State on Void Linking During Ductile Fracture
PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEERING
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Specimens containing arrays of through-thickness holes are used to model aspects of void linking during ductile, microvoid fracture. Specifically, the contrasting deformation and fracture behavior of sheet specimens containing either pairs or pseudo -random arrays of equi-sized holes is examined in both uniaxial and equal-biaxial tension utilizing experiment as well as computer simulation. Our results show for this plane-stress situation that hole linking is always caused by flow localization within the ligaments between neighboring holes. The imposed strains to initiate flow localization and subsequent ligament failure are sensitive to stress state uniaxial versus biaxial, strain hardening, and the location of the neighboring holes. A significant observation is the influence of stress state on the multidirectionality of hole linking paths. As a result, increasing the biaxial component of the stress-state increases the number of holes that can participate in a hole linking process increases. A related and subtle implication to microvoid fracture is that the strain range over which void linking occurs decreases with increasing triaxiality of the stress state in effect, after the initiation of void linking, its propagation is accelerated under biaxial or triaxial tension.