Deformation and Fracture at Isolated Holes in Plane-Strain Tension.

摘要

The tensile behavior of plane-strain specimens each having a central hole with axis in the zero-strain direction has been examined. The study is based on the contrasting behavior of two materials, one with a relatively high strain hardening rate (an HSLA steel) and the other with a low rate (Ti-6Al-4V). Deformation of the holes, associated necking of the ligaments, as well as the overall force-elongation response exhibits excellent agreement with predictions from a large-strain elastoplastic finite-element model. Failure of the high strain-hardening material occurs by ductile tearing across the ligaments whereas failure of the low-hardening material occurs by shear localization. This is consistent with the predicted incremental plastic strain distributions as calculated by the finite element method. The experimental results and predictions of the finite-element models indicate the importance of work hardening in diffusing plastic flow in the presence of a geometric inhomogeneity. (Author)