A multisurface model for gradient‐enhanced damage coupled to finite plasticity

Abstract

AbstractA gradient‐enhanced damage formulation is coupled to isotropic plasticity in the framework of finite strains. Within the finite element method, an additional field variable representing nonlocal damage is introduced and linked to its local counterpart in order to allow a standard local formulation at the material point level. The onset of damage and plasticity is governed by damage and yield criteria respectively. This multisurface approach requires the determination of the two Lagrange multipliers. By using logarithmic strains, a formulation in principal axes in combination with a von Mises yield criterion is implemented. The damage functions are defined by means of exponential functions in order to avoid further constraints on the local damage variable. The model is able to capture a wide range of material responses, ranging from brittle to ductile damage and plasticitiy dominated behaviour. The mesh independence of the model is shown by means of representative finite element examples. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)