Applications of adina to viscoplastic-dynamic fracture mechanics analysis

Nonlinear rate-dependent effects in crack run-arrest events in ductile materials are being investigated through development and applications of viscoplastic-dynamic finite element analysis techniques. This paper describes a portion of these studies wherein various viscoplastic constitutive models, dynamic crack-propagation algorithms, and proposed nonlinear fracture criteria have been installed in the general purpose ADINA finite element computer program. The predictive capabilities of the nonlinear techniques are evaluated through analyses of crack-arrest tests of nonisothermal wide-plate specimens. Values of fracture parameters calculated by elastodynamic and viscoplastic-dynamic techniques are compared to assess the impact of including viscoplastic effects in the computational models. Mesh refinement studies are presented that examine whether the proposed fracture parameters converge to nonzero values in viscoplastic-dynamic analyses or whether they are controlled by element dimensions. Plans are reviewed for additional computational studies to assess the utility of viscoplastic analysis techniques in constructing a dynamic inelastic fracture mechanics model for ductile steels.