Multiscale modeling of fracture in fiber-reinforced composites

The fracture behavior of a fiber-reinforced composite beam in the presence of a notch perpendicular to the fibers is simulated by means of a multiscale model based on an embedded cell approach in three dimensions. The representation of the material in front of the notch tip – where damage is concentrated – included the actual fiber/matrix topology in the composite, while the rest of the beam was represented by a linear thermoelastic, transversally isotropic homogeneous solid. The damage and fracture micromechanisms which control the onset of fracture (namely, plastic deformation of the matrix, brittle fiber fracture and fiber/matrix frictional sliding) were included in the behavior of the different phases and interfaces, and the corresponding micromechanical parameters governing their behavior were independently measured. The mechanical response of the beams in three-point bending was computed using the finite element method, and the simulation results were in good agreement with the experimental data at both the microscopic and the macroscopic level, demonstrating the potential of this approach to simulate the fracture behavior of complex, heterogeneous materials. Finally, further applications of these multiscale applications are briefly noted.