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Ductile failure with gradient plasticity coupled to the phase‐field fracture at finite strains
Author(s) -
Aldakheel Fadi,
Raina Arun,
Miehe Christian
Publication year - 2015
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201510126
Subject(s) - plasticity , classification of discontinuities , materials science , discretization , coalescence (physics) , von mises yield criterion , complex fracture , stress field , mechanics , void (composites) , nucleation , discontinuity (linguistics) , brittleness , phase field models , finite element method , fracture (geology) , structural engineering , phase (matter) , composite material , physics , mathematics , engineering , mathematical analysis , thermodynamics , quantum mechanics , astrobiology
Most metals fail in a ductile fashion, i.e, fracture is preceded by significant plastic deformation. The modeling of failure in ductile metals must account for complex phenomena at micro‐scale, such as nucleation, growth and coalescence of micro‐voids. In this work, we start with von‐Mises plasticity model without considering void generation. The modeling of macroscopic cracks can be achieved in a convenient way by the continuum phase field approaches to fracture, which are based on the regularization of sharp crack discontinuities [1]. This avoids the use of complex discretization methods for crack discontinuities and can account for complex crack patterns. The key aspect of this work is the extension of the energetic and the stress‐based phase field driving force function in brittle fracture to account for a coupled elasto‐plastic response in line with our recent work [3]. We develop a new theoretical and computational framework for the phase field modeling of ductile fracture in elastic‐plastic solids. To account for large strains, the constitutive model is constructed in the logarithmic strain space, which simplify the model equations and results in a formulation similar to small strains. We demonstrate the modeling capabilities and algorithmic performance of the proposed formulation by representative simulations of ductile failure mechanisms in metals. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)