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A new approach is presented to convert X-ray microcomputed tomography (μCT) image data of as-manufactured fiber-reinforced microstructures into high-fidelity finite element (FE) meshes. The mesh-generation approach leverages existing image segmentation and meshing tools to generate FE meshes of a woven-fabric and fiber-reinforced composite (FRCs), where constituents in each microstructure are represented explicitly. Segmentation of fibers from X-ray μCT images was performed using a template-matching/Kalman-filter estimation algorithm, and flaws were segmented using Trainable Weka Segmentation. Segmentation data were converted into reduced-order images, which were subsequently imported into Simpleware™ for mesh generation. To demonstrate advancements of the mesh-generation process, biaxial and uniaxial FE simulations were performed in Abaqus® for the woven- and FRC microstructures, respectively. Results reveal that the mesh-generation approach allows for modeling of distinct interactions between constituents, including contact/friction between fibers and interactions at the fiber-matrix interfaces. Results from this work demonstrate that X-ray μCT images of complex fiber-reinforced microstructures can be converted into high-fidelity meshes, but the high number of elements required for discretization necessitates additional work to improving mesh efficiency.

The aim of this study is to investigate progressive formation of cryobiaxial-induced damage in tape-laminate composites intended for use in space-launch-vehicle cryotanks. A new test method is developed to evaluate three stacking sequences subjected to biaxial loading at room and liquid-nitrogen temperatures. Ex situ X-ray computed tomography is used intermittently between loading intervals to image formation and progression of ply-level damage. The mechanisms governing damage evolution are found to be the same for all stacking sequences, regardless of test temperature; however, at a given mechanical load, the low-temperature specimens exhibit significantly more cracking due to increased thermal-residual stresses. In all cases, ply damage is dominated by formation of stitch cracks, which only propagate through-thickness when the relative angle between adjacent plies is less than 45°. Based on findings in this study, a set of guidelines are proposed for the design of tape-laminates that are resistant to cryobiaxial-induced loading.