Computational Methods for Viscoplastic Dynamic Fracture Mechanics Analysis.

摘要

The role of nonlinear rate-dependent effects in the interpretation of crack run-arrest events in ductile materials is being investigated by the Heavy-Section Steel Technology (HSST) program through development and applications of viscoplastic-dynamic finite element analysis techniques. This paper describes a portion of these studies wherein various viscoplastic constitutive models and several proposed nonlinear fracture criteria are being installed in general purpose (ADINA) and special purpose (VISCRK) finite element computer program. The constitutive models implemented in these computer programs include the Bodner-Parton and the Perzyna viscoplastic formulations; the proposed fracture criteria include three parameters that are based on energy principles. The predictive capabilities of the nonlinear techniques are evaluated through applications to a series of HSST wide-plate crack-arrest tests. To assess the impact of including viscoplastic effects in the computational models, values of fracture parameters calculated in elastodynamic and viscoplastic-dynamic analyses are compared for a large wide-plate test. Finally, plans are reviewed for additional computational and experimental studies to assess the utility of viscoplastic analysis techniques in constructing a dynamic inelastic fracture mechanics model for ductile steels. 34 refs., 14 figs. (ERA citation 13:040606)