A model for simulating the 3D quadrangular rotary braiding process.

3D quadrangular rotary braiding is one vital technique of high efficiency and flexibility to manufacture preforms for composites. However, the use of this technique is limited to fabricating a few traditional braided fabric structures, which is attributed to the lack of knowledge of its process. Therefore, a model is proposed to simulate the braiding process so as to develop new processes and corresponding fabric structures. First, yarn interlacement patterns under individual propelling of the horn-gear and switch are depicted, which preliminary supplies a reference to the selection of process parameters. Then, the braiding process is digitized based on a novel mixed coordinate system, which constructs the relation between the process and carrier path. Combined with the algorithm transforming carrier path to yarn trajectories, the process-structure model is established. Afterward, the effect of horn-gear and switch movement on the yarn interlacement pattern is illustrated, which further clarifies the utilization principle of braiding process parameters. Several interesting novel braided structures including the surface-core structure are found, which shows the potential of this technique. At last, a new multi-layer interlock structure is created by modifying part of the process parameters of traditional 3D braided structure, which verifies the correctness of above model and effects.