Fracture mechanics of fiber reinforced composites

The present investigation is a study of the stress field produced by a broken fiber in a fiber reinforced composite and the nature of failure propagation in the composite following such an initial break. The material is simulated by a hexagonal network of elastically coupled discrete elements. Equilibrium of a typical element yields a system of first order difference equations in terms of the displacements of the elements. The displacements are then found by the method of relaxation, and stresses obtained from the resulting displacement field. Results are given for various values of relative elastic properties and fiber volume fractions to show the effect of these parameters on stress distributions. Where applicable, results are compared to previous analyses. A theory is offered to explain the general notch insensitivity of fiber reinforced composites based on the distribution of flaws in fibers. A recommendation for future study is included.