Viscoplasticity coupled with nonlocalized damage for incompatibilities due to strain softening

Abstract

The aim of this work is to overcome the deficien-cies of the previous models such as, mesh dependency, nonobjectivity of the numerical response and strain local-ization encountered by using general softening plasticity models. The change of type in the governing partial differ-ential equation can be prevented by introducing rate-dependent 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 distribu-tion 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 construc-tion of a combining approach with emphasis on the use of visco-plasticity theory and nonlocal damage model to con-stitutive modelling of concrete behaviour.