A Plasticity-Like Discontinuous FE Approach for Plain and Fiber-Reinforced Brittle Materials

Abstract

Fiber-reinforced composites are attractive materials due to their good mechanical behavior under general stress states and to their fracture and fatigue resistance. The use of reinforcing fibers is a well-known mechanical-enhancing technique, especially in brittle or quasi brittle materials, and allows us to obtain a better performance with respect to traditional materials. In the present article, a continuum finite element (FE) formulation to analyse fracture mechanics problems in fiber-reinforced or in plain brittle or quasi-brittle materials involving a displacement field discontinuity—produced by crack formation and propagation—is discussed. By employing a cohesive crack approach, an appropriate stress field correction in the above FE formulation is used to simulate the displacement discontinuity (crack), whereas the effect of reinforcing fibers is considered through a micromechanical model, based on energy concepts, which is able to take into account the fiber debonding. The crack bridging stress enhanced due to the fibers is herein determined and considered in the model. Finally, some 2D examples involving plain, fiber and steel rebar reinforced brittle materials are presented in order to evaluate the capability of the proposed computational approach.