Analysis and choice of a numerical model for determining limit moment of a beam subjected to bending using fracture mechanics

The research follows the overall behavior of a reinforced concrete beam subjected to three-point bending by using methods of the fracture mechanics. The model used is based on the discrete crack model, allowing crack growth in the midsection of the beam and is implemented in the ANSYS software product. A specific focus is placed on determining the maximum (limit) bending moment in the midsection as well as on the bearing capacity force of the beam. The change in the limit bending moment, the stresses in the midsection and the force-displacement behavior depending on the class of concrete and the reinforcement ratio considering the crack growth are analyzed. A comparison of three computational models is made. The aim of the study is to choose an appropriate numerical model for determining the limit bending moment and the bearing capacity of a beam considering crack growth and simulating a plastic joint.