Discrete modeling of short-fiber reinforcement in cementitious composites

This article presents a computationally efficient method for analyzing the performance of short-fiber reinforcement in cementitious composites. Each fiber is modeled as a discrete entity. Realistic, nonuniform fiber distributions can be specified as program input. Discrete element systems are used to represent the matrix material. Fiber response is constrained to the kinematics of the discrete elements; the number of system degrees of freedom is therefore independent of the number of fibers. Pre-cracking contributions of the fibers are modeled using an elastic shear lag theory. Post-cracking contributions depend on pullout relations based on the micromechanics of the fiber-matrix interface. In either case, there is a direct link between fiber-local actions and composite response. Numerical results for both aligned and randomly oriented fiber composites are compared with theoretical predictions based on simple mixture rules.