Effect of carrier configuration on the 3D four-directional and full five-directional rotary braided fabric structures

3D rotary braiding process has high flexibility to fabricate various fabric structures which lead to different mechanical properties of composites, but the carrier configuration, a key variable, has not been elucidated. This paper reveals its effect on the braided fabric structures. Potential carrier configurations are discussed and topological models are established based on representative braiding patterns. Yarn geometries are derived according to the mechanism of yarn squeezing, then unit cells are identified. Interior unit cells show total different yarn topologies, which demonstrates that either four-step or surface-core braids can be produced by rotary method. The dimension, yarn orientation and fiber volume fraction have close correlations to carrier configurations, which is attributed to the interlacing density in braiding process. However, the addition of axial yarns in full five-directional fabrics leads to same yarn topology as to eliminate the difference.