Computer Simulation Of Three-dimensional Weft Knitting Jacquard Fabric

3D weft knitting jacquard fabric(WKJF) is welcomed by consumers, and at the same time widely adopted in clothing, furniture industries for its soft touch, superior performance, and convex jacquards patterns. Whether from the mechanical properties' perspective like shape retention, and wrinkle resistance, or heat-moisture comfort features like thermal insulation, moisture permeability, and ventilation, WKJF with elaborate surface patterns has exhibited excellent advantages. Intricate products have been popular in the mid–higher end of the market lately for its sophisticated jacquard fabric, wide range of applications, and highly efficient and environmentally fabricating process.However, the difference between the real fabric and designed 3D convex pattern is still difficult to estimate and normally huge. This has brought problems into design, innovation, and fabrication stage, as well as cost control. First, in order to control the quality of products, manufacturers will have do test knitting to see if the final product yields the designed imput for every design of product. This will delay the actual manufacturing period for 3-5 days, with associated increased costs. Because of this, most domestic manufactures mainly duplicate products in the market to get quicker revenue turnaround and save development costs, which limits the ability to cultivate innovation.This practice may thus develop into a vicious cycle. Secondly, most consumers have difficulty estimation the problem the thickness of the fabric and associated price forecast. The ideal fabrics should have the expected three-dimensional effects at a relatively low price, but a strong contrast results due to a complex design process and high product quality control costs. Compromises in resources spent in research and developments and quality control result in lack of competitiveness in the international market. Finally existing textile sector related computer-aided design(CAD) technology and the single coil system based three-dimensional jacquard weft knitting effect appearance simulation modeling cannot accurately forecast the final product. With smaller coil, larger jacquard size, the traditional CAD simulation coil sets of strings and process technology methods can not reflect the effect of its uneven surface. In addition, the tradeoff of time spent on simulation and how realistic the results are bring this issue into a dilemma.This research, seeks to find a suitable computer simulation to solve the problems associate with three-dimensional jacquard knitted fabric, thereby ultimately minimizing the effect of the previous stated issues. This will not only complement the study and development of computer simulated textile fabrics, but also serve as a theoretical reference for solving the problems related to the simulation of three-dimensional effect of such fabrics. This study mainly includes the discussion and summary on three-dimensional knitted jacquard design methods, sensitivity analysis of the factors influencing the three-dimensional simulation of fabrics. Data collection and establishment of fabric surface model, research about the algorithm used in fabric surface simulation and the establishment of fabric simulation system based on the Unity3 D engine. The following are the main five areas:(1) Review of the characteristics of three-dimensional jacquard knitted fabric, production processes and production equipment. Introduction of the proposed design method for such three-dimensional fabrics. Design summary, features, and Precautions for the main pattern, background pattern, process design and fabric development method and process. The study conclude that the problems in the design and fabrication stages of WKJF are difficulties in pattern design, cost control, lack of innovation, and manufacturing process. The proposal therefore is an adoption of computer simulations to bridge the gap between the two dimension pattern design and three dimension end products. This will improve the success rate of test weaving, reduce the waste in manufacturing resources, and speed up the production process and independent research and development capability in pattern designs.(2) This section presented a summary on the concept of WKJF, as well as the research motivation and methodology. Discussed the three factors that will affect the 3D effect of WKJF, which are raw material, jacquard method, and pattern. Factors like the amount of inlay yarn material, method of one surface or double surface jacquard, different combinations of patterns all have different impacts on the end products. After studying concepts like the difference in material thickness, curvature of surface, the conclusion is that the two main factors that affects the appearance of the end product are the change in height and corresponding width of one single loop. The study of the surface curvature is the basis of WKJF modeling.(3) Established the simulation of the surface of fabrics from a macro perspective, which surpassed the traditional single loop based simulation was carry out. The fabric surface model generated based on data collected by threshold sampling experiments, quantified jacquard fabric surface data, and Kriging interpolation algorithm can basically represent the surface pattern caused by the difference between the material thicknesses. The model was also improved using the curvature function of the pattern area, which could better represent the appearance of the jacquard fabric and providing data support for the fabrics simulation.(4) For the balance of simulation speed and how realistic it is, an algorithm for more complicated jacquard fabrics surface was adopted. The mesh of the model was constructed based on the particle system. Based on specifying specific parameters like the heights of pattern, the width of the corresponding patter, the number of iterations, and the number of subdivisions, matching the simulation results to the real data collected, a combination of the generated less-detailed simulation results with normal mapping technology was used to display the surface patterns of the fabrics. This provides the theoretical support for the new 3D simulation method for WKJF. A superior surface simulation results could be generated with optimized time spent.(5) The construction of three-dimensional knitted jacquard computer simulation system was completed. Advantages of the Unity3 D engine, such as cross-platform feature, high efficacy, real-time simulation display, script compatibility, and system interactions, are essential to the simulation model. The model applies rapid prototyping to achieve system architecture, deployment of the files, class design, UI design, and display. The end user could follow either wizard-style or menu driven approach to run the simulation. The biggest achievement of it is that the end user could generate the final result by adjusting settings like, category and surface density of the raw material, and fabrication methods. Multiple simulation results could be generated rapidly, 360° display is also available.This study elaboratedly discussed the computer simulation of WKJF. Motivated by the real industrial problems, this study is deemed as a research processe. That could be applied as a reference for the design stage, the develop ment stage, and the fabrication stage of WKJF in an industrial setting, as well as for the studying of computer aided fabrics simulation system.