Textile Structure
how cloth is put together
Concept

Tension — where it appears

The pull carried along a thread or a sheet of cloth, which it can bear where a push would make it buckle. In a stretched or draped cloth it sets how closely wrinkles are spaced, against the bending stiffness that resists folding them tightly.

Named by 2 essays across one field — each of them below, with the objects they name alongside it.

Wrinkles 127 mm apart. A 300 mm width of a 120 g/m² cloth whose bending length is 20 mm, held under 5 newtons per metre across it and compressed. It cannot carry the compression in the plane, so it leaves the plane, at a wavelength the bending rigidity and the tension settle between them: 127 mm, which is 2.4 wrinkles across the width. The amplitude is drawn and is not computed — this arithmetic sets the spacing and says nothing about the depth.

A cloth cannot carry a push

The net model that runs this site's mechanics has no bending stiffness at all, so it buckles under any compression whatever, into wrinkles of any wavelength whatever. What picks the wavelength is the competition the net leaves out — and the answer is a quarter power, which is why a wrinkle is so hard to change.

mechanics · Buckling One surplus, three depths, one slope. A 300 mm width of three cloths under 5 newtons per metre, each shortened by 1.0%, drawn at one scale in both directions. a chiffon has wrinkles 43 mm apart and 1.4 mm deep; a shirting has wrinkles 127 mm apart and 4.1 mm deep; a coating has wrinkles 249 mm apart and 8.0 mm deep. All three leave the plane at the same steepest slope, 11.5°, because that slope is set by the surplus alone.

A stiff cloth's wrinkle is deeper and no steeper

Stiffness sets how far apart a wrinkle's crests lie, and the surplus length it has to hide sets the rest. Scale a wrinkle up and its slopes do not change, so one per cent of surplus leaves a chiffon, a shirting and a coating all at 11.5 degrees, 1.4 to 8 millimetres deep. The steepness has no cloth in it — and steepness is what a light reads.

mechanics · Buckling

Named alongside it

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

Bending lengthBucklingFlexural rigidityInextensibleWrinkleCantileverDrapeDrape coefficientElasticaTrellis

All concepts