Title: Modelling of size effects in concrete using elasto-plasticity with non-local softening

Author(s): J. Bobiński, J. Tejchman

Publication: KILW

Volume: 52

Issue: 1

Appears on pages(s): 7-35

Keywords: finite element,size effects

DOI:

Date: 1/1/2006

Abstract:
The paper presents numerical FE-simulations of size effects in quasi-brittle materials like concrete performed under plane strain conditions. The material was modeled within elasto-plasticity with isotropic hardening and softening. A linear Drucker-Prager criterion with a non-associated flow rule was defined in the compressive regime and a linear Rankine criterion with an associated flow rule was adopted in the tensile regime. To ensure the mesh-independence and to capture size effects, both criteria were enhanced in a softening regime by non-local terms to include a characteristic length of micro-structure. FE-analyses of 3 different boundary value problems with respect to a size effect was performed for uniaxial tension, uniaxial compression and three-point bending using various ratios between the characteristic length of microstructure and a concrete specimen size. The numerical results for uniaxial tension and bending were compared with the size effect law by Bazant. In addition, the size effect was numerically investigated in a reinforced concrete beam without stirrups subject to bending, where a perfect bond between concrete and reinforcement was assumed.