Size Effect Analysis of Concrete Beams Under Bending Using Crack-Band Approach

Abstract

Analysis of size effect phenomenon in quasi-brittle materials is presented in this research using damage plasticity model. Notched and unnotched specimens under three-point bending fracture test are analyzed by setting a 3D finite element model. For this purpose, Abaqus software is utilized. Concrete damage-plasticity model (CDPM) enhanced with crack band approach is used to conduct simulations of concrete specimens. The efficiency of this model is investigated especially for size effect phenomenon. 2D finite element model is setup for three-point bending beams in order to estimate fracture parameters for specific span to depth ratio, L/D=2.176. The simulations are conducted for each different notch depths. 8-node quadratic plane stress elements are used to define 2D domain and singularity field at the notch tip is modeled using quarter point technique. Energy release rate is calculated using J-integral approach. Obtained results are compared to experimental ones reported in literature and are also compared to the Bazant’s size effect law. This study shows that concrete damage-plasticity model enhanced with crack band approach can capture size effect observed in concrete-like materials’ fracture.