Abstract:

Objective Owing to the procedural intricacies in the production of double needle bar pile fabrics, the pace of product innovation is sluggish, and the design cycle is protracted. Presently, simulations of pile fabrics are conducted at a holistic level, lacking in-depth investigation pertaining to loop-based structures. Consequently, this paper aims to achieve simulations of double needle bar pile fabrics grounded in loop-based structures, thereby enhancing simulation efficiency.

Method This paper establishes a digital and threading mathematical model of yarn, By adding a control nodes at the pile stretching lines, the broken stretching lines is controlled to simulate the effect of pile fibers, and a random.Next() function is used controls the rotation angle of the pile, adjusts the position of the control nodes using a calculation formula to make the pile appear in a random bending state, and establishes a loop and weft insertion pile model.

Results Through the process design of loop and weft insertion pile fabrics, the knitting technique was studied, and the mathematical model of the guide needle movement and yarn threading was established. The plush formed by both needle front padding and needle back padding is called looped pile. The plush fabric that is only used for needle back padding and not for needle front padding is called weft insertion pile. The structural characteristics of the loop and weft insertion pile were analyzed, and the design process and knitting characteristics were combined to establish loop and weft insertion pile model. The pile loop model was divided into a fundamental loop model segment and a pile segment. The fundamental loop segment was mainly used for displaying the piercing of the back pile organization and the ground organization, while the pile segment was exposed on the fabric surface post-finishing. The loop for loop pile consists of ten control nodes, with two additional nodes added at two stretching lines. Similarly, the weft insertion pile loop comprises six control nodes, with one additional node at each of the two stretching lines. The control nodes are connected using Bezier curves to form the loop model. The rotational height of the pile segment remained constant, while the length of pile fibers changes with the rotation angle of the pile fibers. The rotational angle was generated using random functions in the C# programming language. This determines the bending direction, simulating the pile's bending effect. With each pile fiber's rotational angle being random, increasing the number of pile fibers at the stretching lines resulted in their dispersion, and a higher fiber count would lead to a denser and more pronounced pile pattern, enhancing the realism of the pile fabric's three-dimensional simulation.

Conclusion The establishment of loop and weft insertion pile structural models has facilitated the three-dimensional simulation of double needle bar warp knitted pile fabrics, addressing the issue of extended design cycles and enhancing production efficiency. This advancement has propelled the widespread adoption of double needle bar warp knitted pile fabrics in various markets, including home textiles, automotive seat cushions, sofa coverings, curtains, and other related fields.

Key words: warp knitting, double needle bar, pile fabric, mathematical model, three-dimensional simulation