Forming analysis of three-dimensional angle-interlock structures with warp insertion and its composites’ compressive property

Three-dimensional angle-interlock woven composites (3DAWCs) are characterized by lightweight and high strength and their compressive performance can be further improved by introducing warp insertions. The influencing mechanism of warp insertions on the internal yarn morphology and compression performance of 3DAWCs was explored through experimental characterization and virtual fiber model. The experimental results shows that the warp insertions can improve the orientation of warp yarns in 3DAWCs and enhance the warp compressive performance; at the same time, warp insertions can cause the undulation of weft yarns, leading to a decrease in weft compressive performance. Compared with the sample without warp insertions (AWC0), a high warp insertion ratio sample (AWC2) can increase the warp compressive strength by 90.7%, but may reduce the weft compressive strength by 39.9%. In addition, the warp insertion propo§rtion has a significant impact on the warp and weft compressive failure morphology of 3DAWCs. For the sample with a high warp insertion ratio, the warp compressive failure mainly occurs at the ends, while the weft compressive failure mainly presents shear failure. Through virtual fiber model analysis, the formation mechanism of yarn morphology is revealed. It is found that the introduction of warp insertion may lead to a change in the interaction state between the warp and weft yarns, resulting in the weft yarns to undulate.