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Modelling macroscopic imperfections for the prediction of flow localization and fracture
Author(s) -
BARLAT F.,
RICHMOND O.
Publication year - 2003
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1046/j.1460-2695.2003.00470.x
Subject(s) - coalescence (physics) , porosity , materials science , void (composites) , forming limit diagram , volume fraction , nucleation , plasticity , mechanics , fracture (geology) , composite material , structural engineering , thermodynamics , engineering , sheet metal , physics , astrobiology
Ductile materials subjected to plastic deformation experience the different stages of void nucleation, growth and coalescence that eventually lead to ductile fracture. Several models have been proposed to assess the influence of this damage on flow localization and fracture. In general, the plastic behaviour is represented by a constitutive model for porous or damaged materials. It is typical to introduce a material imperfection, with porosity higher than average, which evolves up to localization and fracture. However, the void volume fraction in the imperfection is chosen more or less arbitrarily. In the present work, a model that evaluates this void volume fraction more rigorously is developed. The forming limit diagram (FLD) for a dual phase‐steel is calculated using the damage‐based imperfection calculation and validated with experimental results. The effect of void shape on the imperfection porosity level and limit strains in sheet forming is also assessed with the present method.