Finite element simulations of fiber pullout toughening in fiber reinforced cement based composites

The role of fibers in fiber reinforced cement based composites was studied by means of finite element method. The first step simulated the fiber pullout from a cementitious matrix and resulted in pullout force versus slip displacement response. In the composite response simulations, the fibers across a prescribed crack length were modeled as nonlinear spring elements. The pullout force versus slip displacement was used for the stiffness of the spring elements. J-integral was evaluated for the two cases of with and without fibers, and the difference between the two was used as the toughening contribution of fibers. The fiber toughening effect was studied for different fiber lengths and interface parameters.