The Impact of Elongation on Change in Electrical Resistance of Electrically Conductive Yarns Woven into Fabric

Abstract

Electrically conductive yarns (ECYs) are gaining increasing applications in woven textile materials, especially in woven sensors suitable for incorporation into clothing. In this paper, the effect of the yarn count of ECYs woven into fabric on values of electrical resistance is analyzed. We also observe how the direction of action of elongation force, considering the position of the woven ECY, effects the change in the electrical resistance of the electrically conductive fabric. The measurements were performed on nine different samples of fabric in a plain weave, into which were woven ECYs with three different yarn counts and three different directions. Relationship curves between values of elongation forces and elongation to break, as well as relationship curves between values of electrical resistance of fabrics with ECYs and elongation, were experimentally obtained. An analytical mathematical model was also established, and analysis was conducted, which determined the models of function of connection between force and elongation, and between electrical resistance and elongation. The connection between the measurement results and the mathematical model was confirmed. The connection between the mathematical model and the experimental results enables the design of ECY properties in woven materials, especially textile force and elongation sensors.

Keywords: electrically conductive yarn; elongation; plain weave; resistance; tensile force; woven fabric.

Figure 1

Scheme of the series measuring circuit.

Figure 2

Characteristic diagrams of the tensile force–elongation (F-ε) curve of the woven fabric and the electrical resistance–elongation (R-ε) curve of the conductive fabric yarn.

Figure 3

Fabric samples with woven ECYs: (a) sample cut in the weft direction (0°); (b) sample cut in the warp direction (90°); (c) sample cut at a 45° angle.

Figure 4

System for measuring changes in the electrical resistance of woven conductive yarns.

Figure 5

Photo of the measuring system.

Figure 6

Force–elongation (F-ε) and electrical resistance–elongation (R-ε) diagrams for fabric samples cut in the warp direction: (a) for sample X-0; (b) for sample Y-0; and (c) for sample Z-0. (d) Experimental and mathematical models of F-ε and R-ε curves for sample Y-0.

Figure 6

Force–elongation (F-ε) and electrical resistance–elongation (R-ε) diagrams for fabric samples cut in the warp direction: (a) for sample X-0; (b) for sample Y-0; and (c) for sample Z-0. (d) Experimental and mathematical models of F-ε and R-ε curves for sample Y-0.

Figure 7

Force–elongation (F-ε) and electrical resistance–elongation (R-ε) diagrams for fabric samples cut at a 45° angle: (a) for sample X-45; (b) for sample Y-45; and (c) for sample Z-45. (d) Experimental and mathematical models of F-ε and R-ε curves for sample Y-45.

Figure 8

Force–elongation (F-ε) and electrical resistance–elongation (R-ε) diagrams for fabric samples cut in the weft direction: (a) for sample X-90; (b) for sample Y-90; and (c) for sample Z-90. (d) Experimental and mathematical models of F-ε and R-ε curves for sample Y-90.

Figure 9

Correlation between the slope of the line k of force and the slope of the line p of electric resistance for samples: (a) X-0, Y-0, and Z-0; (b) X-45, Y-45, and Z-45; and (c) X-90, Y-90, and Z-90.