Abstract:

Objective In order to realize the efficient design and simple formation of warp knitted spacer shoe fabrics, the structure and forming principle of shoe fabrics are studied, the application benefit of spacer shoe fabrics is explored, and a design method of spacer shoe material is proposed. With the help of JavaScript and C # computer programming language, fast 3-D simulation of several types of spacer shoe fabrics is carried out with different mesh structures, enriching the choices of the mesh spacer shoe materials.

Method The functional structure of different areas of the shoe upper was divided, and the matrix model of process design was established, including the mathematical model of yarn padding number and threading cycle. 3-D loop models of 8-point unit loop, 2-point weft lining, 16-point double warp knit structure were constructed. The classification table of the retransmitted structures was listed by using the transverse displacement difference between the needle and the back of the needle. The stress analysis of the rerun loop and the spacer loop was carried out.

Results The vamp divided into different mesh areas according to functional requirements. Large mesh is used at the toe to improve breathability, small mesh is used at the toe cap and heel area, and tight structure was used at the hem to improve wear resistance (Fig. 1). The construction principle of the 3-D structure of the 4-comb spacer vamp fabric was analyzed. The re-woven weave can be applied to the top and bottom woven surfaces, and the mesh and pattern are only formed on the top or bottom (Fig. 2). The mathematical matrix was used to visually represent the padding number of the spacer shoe fabric and the warp cycle. The knitting action was expressed according to formula of the front and back needle transverse movement difference. Based on the loop control points, the basic 8-point single-needle loop, 16-point double-needle double-needle loop, and 2-point weft lining 3-D models were established, focusing on the hierarchical relationship between the double-needle loop and the two loop on the horizontal single-needle, and the classification table of the double-needle tissue was established according to the transverse movement of the needle back before the needle (Fig. 4, Tab. 1, Fig. 5). According to the formation mechanism of mesh in the spacer shoe material, stress analysis was carried out on both longitudinal lines, and the stress solution of the spacer wire loop in the 3-D space is also carried out (Fig. 6 and Fig. 7). According to different functional requirements, three types of spacer upper fabric processes with different mesh structures were designed, including raw material, knit structure, warp cycle, warp let-off and other parameters. 3-D simulation of three types of spacer mesh upper fabrics was set up using C# and JavaScript programming languages. The comparison between the physical image and the simulation image was shown (Fig. 8, Fig. 9 and Fig. 10).

Conclusion On the basis of summing up and analyzing the structural characteristics of the interval mesh shoe material, using the practical significance of the mesh structure in the shoe material fabric, the relevant technological mathematical model and geometric model are constructed, the mechanical analysis of the tension on the loop during the fabric knitting and the calculation of the corresponding offset are carried out, and the application of the warp weave structure is discussed, which provides a new idea for the design of the three-layer structure warp knitted shoe material. It provides reliable technical support for three-dimensional mesh simulation of Jacquard shoe fabric.

Key words: warp knitted shoes fabric, spacer fabric, loop model, loop force, 3-D simulation