Parametric analysis of dynamic crack propagation of concrete bending beam based on the extended finite element method

Abstract

The fracture properties of concrete are affected by various factors, including material parameters and crack geometry parameters. In the paper, pure mode I fracture and mixed mode fracture of concrete bending beams under impact load were studied experimentally and numerically. Numerical models by applying extended finite element method based on the cohesive crack model were employed to simulate pure mode I fracture and mixed mode fracture of concrete bending beams, an experimental program was conducted to validate the numerical models. The effects of material parameters as well as crack geometry parameters on the fracture properties of concrete bending beams were discussed and the most sensitive parameter to affect the fracture properties of concrete bending beams was determined based on the numerical simulations. The results show that the simulation results match reasonably well with the experimental results. For pure mode I fracture, concrete strength grade is proved to have less influence on the fracture properties of concrete bending beams under relative high strength grade condition; Elastic modulus was determined to have the greatest impact on the fracture properties of concrete bending beams, followed by tensile stress, initial crack length and fracture energy; however, Poisson ratio have almost no effect on the fracture properties of concrete bending beams. For mixed mode fracture problem, the influences of initial notch position on crack propagation path can be expressed as a competition between mode I fracture and mixed mode fracture, with offset parameter increasing from 0.0 to 1.0, the fracture failure mode of concrete bending beams changes from pure mode I fracture to mixed mode fracture, followed by both mode I and mixed mode fractures, and finally translates to mode I fracture.