A novel numerical model of debonding of FRP-plated concrete beam

Accurate modeling is required to estimate the debonding in a plated fiber-reinforced polymer (FRP) concrete beam. In the present investigation, a numerical method is developed to model a crack in the FRP–concrete interface. An initial notch is located at the mid-span of the concrete beam. A modified crack closure integral method is implemented to model Mode-I fracture in the concrete. In the present research, a special interface element is formulated to simulate and to predict the distribution of interfacial shear stresses by using drilling degrees of freedom in the nodes of interface elements. Cohesive forces in the nodes of interface elements are formulated by finite element methods. A crack propagation criterion is presented to evaluate when the crack grows in FRP–concrete interface. If the principal stress in the node at the tip of an interface element reaches the maximum shear stress along the FRP–concrete interface, debonding happens. The model is robust, accurate, independent of mesh size, and it is able to model the crack growth in the concrete and debonding of the FRP–concrete interface, simultaneously. The model presented in this study showed acceptable similarity to previous research data.