36—AN ENERGY ANALYSIS OF THE MECHANICS OF WEFT-KNITTED FABRICS BY MEANS OF OPTIMAL-CONTROL THEORY PART III: THE 1 × 1 RIB-KNITTED STRUCTURE
Titel:
36—AN ENERGY ANALYSIS OF THE MECHANICS OF WEFT-KNITTED FABRICS BY MEANS OF OPTIMAL-CONTROL THEORY PART III: THE 1 × 1 RIB-KNITTED STRUCTURE
Auteur:
de Jong, S. Postle, R.
Verschenen in:
The journal of the Textile Institute
Paginering:
Jaargang 68 (1977) nr. 10 pagina's 324-329
Jaar:
1977-10-01
Inhoud:
The general energy analysis formulated to study various areas of fabric mechanics is applied to relaxed 1 × 1 rib weft-knitted fabrics and also to the effects of the application of tension to the structure. The boundary conditions for the 1 × 1 rib structure are derived by assuming half-loop symmetry. Typical solutions are presented in terms of the curvature along the length of the half-loop, the projections of the half-loop shape, the distributed forces, and the nature of yarn contact in the regions of loop-interlocking. Because of intolerably slow convergence of the computer program, it is not possible to include all the five possible conditions of jamming in the solution for 1 × 1 rib fabrics. However, it is confirmed that the 1 × 1 rib structure is naturally jammed in the width direction between adjacent ribs, and the magnitude of the jamming force is estimated. Suggestions for improving the convergence of the computer program are contained in the appendix to this paper. A comparison with the results for the plain-knitted structure shows that rib fabrics are generally slacker structures, i.e., the yarn-interlocking forces are generally lower (about one-half for the 1 × 1 rib compared with the plain-knitted structure when expressed in terms of dimensionless parameters). It is also shown that the ratio of yarn torsional rigidity to yarn bending rigidity, G/B, has only a very minor influence on the loop shape for both 1 × 1 rib and plain-knitted fabrics. Finally, some suggestions are presented for extending the work to other fabric constructions, especially double-knitted fabrics.
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