Viscoplasticity coupled with nonlocalized damage for incompatibilities due to strain softening

Abstract

The aim of this work is to overcome the deficiencies of the previous models such as, mesh dependency, nonobjectivity of the numerical response and strain localization encountered by using general softening plasticity models. The change of type in the governing partial differential equation can be prevented by introducing ratedependent models such as visco-plasticity. Despite the fact that viscosity prevents the strains from becoming infinite at localization, but the localization zone tends to an infinitely small size. When localization occurs, damage is confined in an infinitely small zone and its discontinuous distribution conflicts with the supposed smoothness of the damage variable. The necessary smoothness of the damage field can be ensured by using localization limiter in addition to viscous regularization. This paper focuses on the construction of a combining approach with emphasis on the use of visco-plasticity theory and nonlocal damage model to constitutive modelling of concrete behaviour.