Voids and fiber waviness are two of the most common types of defects induced during the fabrication process of composites. The objective of this work is to quantify the negative effects of these defects on the load bearing capacity of AS4/8552 composite structures. Three-dimensional representative volume elements (RVEs) are created with fiber, matrix, and interface elements to model composite structures for use in a micromechanics-enriched finite element modeling framework. Defects such as fiber waviness, matrix porosity, and nonuniform fiber distributions are explicitly described in the model to predict the response and failure properties of the RVE. To produce a high-fidelity model that can accurately predict the measured ply level material properties, studies are performed on the fiber spacing, fiber diameter, and the number of fibers in the RVE. Single loading cases are applied to the RVE and the results for the loading cases of transverse compression, transverse tension, shear, longitudinal tension, and longitudinal compression are presented. In general, fiber waviness and voids lower strengths of the composite and even change failure mechanisms in some cases. A digital material mode is developed to characterize the effects of defects on ply-level properties based on the micro-level model predictions. To demonstrate the effects of defects on a ply-level component, an open-hole compression test case with a horizontal and vertical void near the drilled hole is analyzed using the material property reduction data from the micro-level model. Results show agreement with experimental data, demonstrating the effectiveness of the micromechanics-enriched modeling approach.
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