The matching relation analysis of yarn pre-tension in weaving 3D bi-directional angle-interlock fabrics

Yarn pre-tension is an important technological parameter in the weaving process and significantly affects the geometry and properties of woven composites. 3D bi-directional angle-interlock (3DBA) fabrics have the same yarn crimp in the warp and weft directions, which requires a special matching relationship between the warp and weft yarn tensions applied in the weaving process. This study focused on obtaining the pre-tension matching relationship that applied between the warp and weft yarns in the weaving of 3DBA fabrics. A quasi-static mechanical model of yarn interactions in the weaving of 3DBA fabrics was developed based on the 2D woven fabric yarn interaction model. The weaving process of 3DBA fabrics could be divided into two interweaves as one cycle. In a given interweaving of a single group of yarns, the pre-tension applied to the warp yarns tends to increase irregularly with the position of the interweaving point and varies linearly with the weft pre-tension. The weft crimps distribution of 3DBA fabrics was compared when yarns were applied to the different proportions of pre-tension in the weaving process. The experiment result shows that the sample with the best uniform distribution of yarn geometry is the one to which the yarn pre-tension calculated by the model is applied in the weaving process. The result provides theoretical support for warp and weft pre-tension applied in the 3DBA fabrics weaving process.