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The deformation behavior of single-layer braided fabric and its influence on the fracture modes of composite tubes under quasi-static axial compression were studied. By changing the parameters of the manufacturing process, braided fabrics with varying structures were produced and were further cured into braided composite tubes. Quasi-static compression experiments were conducted on the tubes, and the crush process was recorded on camera to analyze the deformation of the braided fabric. By employing the finite element method, a numerical model of a composite tube at the yarn scale was established to further verify the role of braided fabric in the process. Two fracture modes that depended on the fabric structure were also observed. The tension in the braiding yarns in the bucking section tends to cause them to separate. Braiding structures with larger braiding angles and more interlacing points between yarns provided more resistance to prevent yarns separating from the braided structure and led to a folding fracture mode. In contrast, a splaying fracture mode occurred in braided fabrics with smaller angles. [ABSTRACT FROM AUTHOR]

Accurately identifying various meso-morphological features and sub-phases within the damaged braided composite fabric is crucial for assessing the mechanical properties of composites under complex loading conditions and different processing parameters. However, obtaining 3D reconstructions that can be quantitatively analyzed is still a challenge, primarily due to the low contrast of the meso-morphological features (yarn tow and matrix crack networks). In this work, a new data enhancement algorithm is proposed to generate a realistic-looking artificial training dataset for enriching the information of the meso-morphological features. Then, the effect of various training networks and training parameters (the size of real and hybrid training dataset, number of epochs) on segmentation performance were examined. Finally, the meso-morphological features were statistically analyzed to accurately evaluate the mechanical properties of the composite material. The work presented here provides an effective tool that enables the quantitative analysis of the dynamic crack evolution process under the axial load of the composite materials. [Display omitted] [ABSTRACT FROM AUTHOR]