A numerical model for FRP-concrete delamination

A numerical model for the study of delamination of Fiber Reinforced Plastics (FRP) glued on concrete specimens is presented. A non linear interface law is adopted, taking into account non linear behavior of concrete cover and adhesive subject to high shear stresses. A non linear system of equations is then obtained via Finite Difference Method. In the proposed Newton-Raphson algorithm, different control parameters can be adopted in the various phases of delamination process (alternatively force or displacements variables). Some numerical simulations are presented, concerning different delamination test setups and bond lengths. Numerical results agree well with experimental data reported in the literature. It is also shown that pull-pull setup, typically adopted for delamination tests, presents a snap-back branch for long FRP-concrete bond lengths. A second setup is also numerically simulated, characterized by a stable propagation of plate delamination.