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This study investigated and compared the performance of ballistic protection panels formed with 100% woven and 100% unidirectional nonwoven para-aramid fabrics at different fabric ply numbers. For this purpose, Twaron CT 710 type woven para-aramid fabric panels and K-Flex unidirectional nonwoven para-aramid fabric panels (which were formed by using Kevlar 129 yarns) of different ply numbers were subjected to ballistic tests according to NIJ standards. Ballistic performance of the test samples was determined by measuring trauma depth and trauma diameter. The energy absorbed by fabric layers and the energy transmitted to the back of fabric layers were calculated from trauma depth and trauma diameter values. It was shown that the unidirectional fabric panels absorbed around 12.5—16.5% more energy than woven fabric panels for the unit panel weight.

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Damage and mechanical properties in textile composites are closely connected with the textile reinforcement’s internal structure. This paper reports and discusses a study of the mechanical behavior and damage of a 2 × 2 twill woven carbon/ epoxy composite resulting from uniaxial tension in the warp and bias directions. A damage investigation was performed by using acoustic emission and full-field strain optical measurements, as well as X-ray and optical microscopy. As a result of the tests, the mechanical properties and strain values of the composite’s damage threshold were determined. Damage initiation when loaded in the warp and bias directions occurred between 0.2% and 0.3% and 0.88% and 1.71% of the applied strain, respectively. Microscopic examination showed that damage or cracks initiated where the yarn was crimped and at interactions between the warp and filling yarns. Full-field strain measurements highlighted the relation between the strain concentrations that are linked with the damage initiation and the reinforcement structure.