Numerical Test Method for Random Chopped Fiber Composites

A two-scale approach for numerical determination of composite material constants using a finite element model is developed. A representative volume element is numerically generated using a modified sequential adsorption algorithm. To determine the strength of the composite material, progressive material degradation models are adopted for the matrix, fiber and the fiber/matrix interface. The epoxy resin is modeled with a modified von Mises criterion in which the effect of hydrostatic stress on yield is accounted for. The resin’s elastic constants degrade with increasing loading application. The glass fiber is modeled as an isotropic material whose failure is governed by the maximum strain criterion. A traction-separation type cohesive zone model is applied at the fiber/matrix interface. Validation of the presented model is achieved by comparing numerical simulations with experimental data. The effective material constants that have been homogenized by the numerical test approach can be applied for future structural analysis.