Textile Structure
how cloth is put together
Concept

Tube — where it appears

A fabric closed on itself, woven as two layers joined at both selvedges or knitted round a cylinder of needles. Woven and knitted tubes are the same object by different routes, and in the woven case one matrix describes both a tube and two cloths.

Named by 6 essays across 4 fields — each of them below, with the objects they name alongside it.

A double cloth. Two complete fabrics woven in one repeat, and what happens when a single intersection is turned over. The layer count beside the draft is computed from the matrix drawn, and the census below it is every single-square change tried in turn.

Backed and stitched constructions

A double cloth is two fabrics woven at once, and the check that verifies it says exactly two. Turn one intersection over and it says one — which means one mistake is enough to destroy the construction, and the enumeration says half of them would do it.

weaves · Integrity tubular, as a graph of its wales. Every wale of tubular as a node — 2 on the front bed and 2 on the back — with one chain per course joining everything that course takes yarn on, because a course is one traverse of one yarn. The nodes are filled by which component they fall into. This structure comes out as 2 fabrics: F0+F1 and B0+B1. The same answer is obtained a second way, by walking every partition of the wales and asking whether any course straddles it, and the two are required to agree.

Does a double jersey hang together

Two beds knitting with nothing passing between them are two fabrics that happen to have been made at once. Of 6,561 two-bed arrays, 1,135 are fabrics and 50 of those are two fabrics — and 28 of the 50 split across the beds rather than along them, so neither half is a layer.

knits · Two-bed How far a tube can be tapered by its loop. The same 10 wales by 10 courses of plain knit at the two ends of the usable loop range for a 20 tex yarn — 3.44 mm at the loose end and 2.80 mm at the tight one — drawn at a common scale in centimetres. On 240 needles the circumference falls from 192.0 cm to 156.0 cm, a taper of 18.8 per cent, and the fabric becomes 1.51 times as dense.

A tube can only be shaped by its loop

On a circular machine the needle count is the cylinder, so a seamless tube's circumference is its wale count times its wale spacing — and the wale spacing is the loop length over one constant. The loop is the only free quantity, the yarn bounds it at both ends, and what is left is a taper of 18.8 per cent bought at the price of a fabric half again as dense.

knits · Shaping A tube. A two-layer fabric 6 ends wide in each layer, with the weft's path drawn across the section below the draft. 1 piece of cloth, 0 free selvedges, 1 shuttle, and a developed width of 12 ends however the edges are joined. The connectivity of the infinite repeat is 2 for this draft and cannot tell this construction from the others.

A tube and two cloths are the same draft

Two separate fabrics, a cloth twice the width of the loom and a seamless tube are the same draft to the last square. The check this site is built on reports two layers for all three and is right every time — because the thing that separates them is four free selvedges, or two, or none, and a repeat has no selvedges in it.

fancy · Double cloth A short-row heel on 64 needles, laid flat. The 32 heel stitches of a 64-needle sock, each column drawn as the courses it was worked in during the short rows: nought at the heel's two edges, rising by four courses a stitch to 42 across the 11 stitches left at the turn. The cells are drawn at the knit's own aspect, a wale 1.2791 times as wide as a course is tall. The instep's 32 columns beside it are worked in none of the short rows. Down the back line the extra length turns the tube through 92.4 degrees, and the whole trapezoid is 65.6 per cent of the fabric a true bend of that angle would need.

A heel turns a right angle because of the loop

A sock's heel is knitted in short rows on half the needles until a third are left, then back out again. Down the back line that adds a length of courses, and a tube's back line longer than its front by that much has turned through π times two thirds over the loop's own aspect — 93.8 degrees, on any needle count, in any yarn. The trade's third is the loop's shape in disguise. What the rule does not do is make a bend: the heel supplies two thirds of the fabric a true right angle needs, and every missing stitch is on its sides.

knits · Shaping Where an air arch first wrinkles under snow over the whole span. A semicircular air arch 4 m across, pinned at both feet, of a tube 200 mm across at 50 kPa, under snow over the whole span; beside it, unrolled from the left foot to the right, the share of the tube's wrinkling budget πpr³/2 spent at each section when the first wrinkle forms, with the thrust's part, N·r/2, shaded darker. The first wrinkle forms 25° above the right foot, at 167 N per metre of span, where the moment of 60.2 N·m compresses the inside of the curve and the thrust is 336 N; there the thrust has taken 21 per cent of the budget. Judged by its moment alone the arch would carry 218.

An air arch pays for its thrust out of its pressure

An inflated tube bent into an arch was expected to start with its inside wall pulled differently from its outside, and to wrinkle where that difference and the load's moment combined worst. It does not: a curved tube is pulled along its length at exactly the straight tube's pr/2, all the way round. What the arch spends its pressure on instead is the thing every arch exists to make — its own thrust — which takes a fifth of the wrinkling budget at the haunch of a shelter arch under snow and more than half on a tight one.

applied · Membrane

Named alongside it

The objects these essays reach for when they reach for this one.

Cloth integrityWaleConnectivityCourseDouble clothMunden constantsSeamlessShapingStitchingBacked clothBeamBuckling

All concepts