Innovative elastoplastic J_2-flow model incorporating cyclic and non-cyclic failure effects of metals as inherent constitutive features

摘要

A new finite strain elastoplastic J_2-flow model is proposed toward directly simulating cyclic and non-cyclic failure effects of metals. The main novelties of this model are as follows: (1) The usual notion of yielding is rendered irrelevant in a more realistic sense of representing elastoplastic behaviors of metals up to failure; (2) The thermodynamic consistency requirement from the second law may be identically fulfilled; (3) Failure effects under cyclic and non-cyclic conditions may be automatically incorporated as inherent constitutive features, with involving neither additional variables nor ad hoc failure criteria; (4) Hardening-to-softening effects of metals up to failure may be effectively characterized in a unified manner. Simulation results are provided and compared with experimental data for monotonic and cyclic failure effects for both uniaxial and torsional deformation modes. In particular, both the Swift effects and the failure effects of twisted metal tubes are simultaneously simulated for four cases of finite torsion, including free-end and fixed-end torsion under monotonic and cyclic loadings, and accurate agreement with finite strain data for both torsional modes is accomplished for the first time.