Three-dimensional Braiding Structures
Three-dimensional integral braiding methods include two-step and four-step braiding processes, with square and circular braiding forms. In the two-step braiding process, the yarns in the preforms are oriented in five spatial directions, with a significant proportion of axial yarns. The basic braiding form of the four-step method contains only braiding yarns, but axial yarns can be added. Within the interior space of the fabric, the yarn orientation can be in four directions. By introducing axial yarns in different directions, three-dimensional preforms with five, six, or seven directional braids can be obtained. Three-dimensional braided preforms can be designed with parameters such as braiding angle, node length, and the number of lining yarns, and altering these parameters can change the properties of the composite materials. However, the braiding width of industrial braiding machines on the market is limited, and the braiding speed is not high, which restricts their widespread application.