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  • Variational phase-field for...
    Dittmann, M.; Aldakheel, F.; Schulte, J.; Wriggers, P.; Hesch, C.

    Computer methods in applied mechanics and engineering, 12/2018, Letnik: 342
    Journal Article

    Variationally consistent phase-field methods have been well established in the recent decade. A wide range of applications to brittle and ductile fracture problems could already demonstrate the ability to predict complex crack patterns in three-dimensional geometries. However, current phase-field models to ductile fracture are not formulated for both, material and geometrical non-linearities. In this contribution we present a computational framework to account for three-dimensional fracture in ductile solids undergoing large elastic and plastic deformations. The proposed model is based on a triple multiplicative decomposition of the deformation gradient and an exponential update scheme for the return map in the time discrete setting. This increases the accuracy on the entire range of the ductile material behavior encompassing elastoplasticity, hardening, necking, crack initiation and propagation. The accuracy and convergence properties are further improved by the application of a higher order phase-field regularization and a gradient enhanced plasticity model. To account for the ductile behavior at fracture, a model of the critical fracture energy density depending on the equivalent plastic strain is proposed and validated by experimental data. •We present a higher order phase-field model to non-linear ductile fracture.•A novel multiplicative triple split of the deformation gradient is introduced.•An exponential update scheme for the return map in the time discrete setting is applied.•To account for ductile fracture a novel model of the critical fracture energy is introduced.•The approach is able to account for the entire range of ductile fracture within non-linear elastoplasticity.