Investigation of crack propagation in plain concrete using Phase-field model

Abstract

Phase-field approach is adopted to investigate numerically the fracture behavior of the plain concrete beams under static load. Simply supported beams under three-point loads are examined. The implementation of the phase-field model is conducted within the commercial finite element software ABAQUS for two-dimensional brittle mode-I fracture problems. The phase-field model is built on the rate-independent variational principle of diffuse fracture. The implementation is based on both subroutines user element (UEL) and user material (UMAT). The elastic displacement and the fracture problem are decoupled and solved separately as a staggered solution. The main variables considered in this study are the length scale parameter, the fracture energy Gf and stability parameter K. The method is verified by comparing the results with a previous experimental study. The results have shown that the length scale parameter have high effect on the ultimate load and it depends strongly on the mesh size. It is also found that the ultimate load increases with increasing the fracture energy Gf, and the change of the parameter K seems not to affect the ultimate load value and the behavior of beams. To investigate the benefits and defects of the phase-field method, the analysis is compared with another numerical method using the eXtended Finite Element Method.