A Geometric Analysis of the Stitch Form of a Circular Plain Knit Fabric Inserted Over a Cylinder

Abstract

The particular stitch used in the legs of pantyhose is one important factor related to wear performance, for example, the way the fabric feels, its luster, etc. To obtain a fundamental knowledge of the stitch form, we analyzed geometrically the stitch form of a circular plain knit model inserted over a cylinder. We developed some formulas that can be used to calculate each of the partial loop lengths from some parameters, such as the radius of a cylinder, yarn diameter, number of courses, number of wales, covered height, and length of yarn in one course, etc., where one loop is divided into eight parts. The formulas include those in the general analysis and an analysis under extreme conditions. Some results from the numerical calculations are shown..','The legs of most pantyhose on the market are made from plain stitch structures produced by circular knitting machines. The leg parts of the hose stretch or contract according to the leg shape and posture of the wearer, and during this, their form changes. The stitch form is generally considered one of the important structural factors related to skin touch, a cool feeling, luster, etc. In previous papers, we postulated that sheer pantyhose made only of regular nylon filament yarns are generally inferior in wear performance and are apt to cause slight skin irritations in women with dry skin or sensitivity to touch because of the particular stitch form under' stretching conditions [ 5,6 ] . That stitch form is one in which the needle loop is rather small and, by contrast, the sinker loop is rather large (Figure 1 ) . Contact between skin and stitches in wear occurs more on the relatively larger contact surface area of the sinker loops with this stitch type than with other kinds of pantyhose, and the resulting friction can clear the skin of sebum or strips the stratum comeum; thus causing skin irritation. Therefore, it. is useful to clarify the mechanism of the stitch form, because it offers fundamental knowledge required to reduce skin irritation.

Loop Length of Plain Single Weft Knitted Structure with Elastane

“…In the past, various geometrical loop models considered more or less porous structures, e.g. open, normal and to a certain degree also closed (compact) structures [2][3][4][5][6][7][8][9][10]12]; however, the yarns used were mostly conventional, i.e. without elastane.…”

“…The subsequent models were more complex [4][5][6][7][8][9][10][11], and played an important role in the control of knitted fabric dimensions and mass per unit area. Later on, loop models [12][13][14][15][16] were designed for graphic simulations and knitted structure planning. Supported by the latest expertise, testing and measuring techniques, e.g.…”

“…Although Morooka & Matsumoto & Morooka's loop model[12] represents the loop as the element of a knitted fabric lying on the cylinder which is a part of a three-dimensional structure, in reality, it is a planar loop model. The authors based this statement with the negligible fabric thickness in relation to the needle and sinker arc within a hosiery fabric.…”

“…The authors based this statement with the negligible fabric thickness in relation to the needle and sinker arc within a hosiery fabric. Morooka & Matsumoto & Morooka[12] presumed an open structure for the general loop shape in which the needle and sinker arcs are in contact neither in the vertical nor in the horizontal direction.With the derivation from the original Morooka & Matsumoto , similar to Peirce's loop model of the open structure and Dalidovich's general loop model. The coefficients of the above mentioned three models differ, since Dalidovich assumes the semicircular shape of the needle and sinker arc, Peirce assumes the straight yarn portions in the semicircular loop crown and straight loop legs, and Morooka & Matsumoto & Morooka assume straight yarn portions only within the needle and sinker arc of the loop.…”

A New Geometric Model of Laid-in Weft-Knitted Fabrics

“…Leaf and Glaskin 20 numerically studied weft-knitted structures, and found that the numbers of courses and wales per inch and the yarn diameters influenced the loop length. Suh, 21 Morooka et al 22 and Eltahan et al 23 proposed geometric models for weft-knitted loops with open, normal, and compact structures, based on the model of Leaf and Glaskin. The model of Eltahan et al resembled that of Peirce, 24 as both were based on a fully compact loop structure.…”