Study On Deformation And Wearability Of Knitted Fabrics

Based on many published articles about the geometry and dimensional properties of knitted fabrics, the structural characteristics of plain knitted fabrics are investigated by large number of experiments. In addition, the complicate double structure-interlock and interlock with missing needles are also concerned. The dimensional properties of cotton interlock and interlock with missing needle are discussed on the basis of definition system for double knits, K values that are used widely to describe the dimensional properties of plain knitted structures are developed into the study of double knitted structures in this paper.A three-dimensional geometric stitch model is presented to describe plain knitted loop in fully relaxed state, which is proved to be practical and consistent with experimental results.In terms of the structural characteristics, the mechanical properties of knitted fabrics are also discussed. As one of the textile structure, knitted fabrics are described as plane orthotropic body with two symmetric axes, and the stress in different direction is approximately linear with strain before the yield point according to hooke's law. Especially, the anisotropy of knitted fabrics is significant and influences physical and mechanical propertiesTraditionally, uniaxial stretching is widely adopted to analyze the physical and mechanical properties of textile products. As a matter of fact, three-dimensional deformation usually takes place in garment during body movement and may involve not only stretching in multi-direction but also shearing, bending and compression. It is suggested that punching behavior of fabric can simulate the wearability of knitted garment during body movement to certain degree. The punching yield strength can be predicted theoretically by developing a mathematical equation from anisotropic effect of knittedfabrics. The experimental results demonstrate the applicability of theoretical formula. Analyses also reveal the factors influencing three-dimensional deforming performance.The excessive stress and strain of knitted garment during body movement cause dissatisfaction perceived by a wearer. It is one of the most important criteria by consumers in judging clothing wearability. To understand the movement comfort of knitted garment, a method of subjectively evaluating this behavior is developed by using psychophysical Stevens' Power Law. Both ranking and rating scales are used as the psychological scales. The two scales are highly correlated with each other, but the rating scale provides more information than the ranking scales and can indicate perceived differences between fabrics.In order to improve the measurement of knits' deformation, some advanced techniques such as Image Processing and Moire method are investigated to combine together. The measurement results indicate that the application of the Image Processing and Moire method made it possible to describe two-dimensional deformation of the distance between adjacent loop centers and the skew angle of loops of knitted fabrics at any point. And this new measurement method will offer new idea to get higher precision and further three-dimensional measurement.