A good sweater is like a cozy hug made of yarn. For that, you can appreciate the friction.
New research reveals how fabrics are knitted can take many forms It can be tailored to fit the contours of your head and body. This effect is the result of friction between adjacent fiber loops that make up knitted fabrics, physicist Jérôme Crassou and colleagues report in a December 13 paper. physical review letter.
Stretch the knit fabric and release it, it will return to its original shape. Some may imagine that fabric is like a rubber band, always returning to its previous size and shape. But “there is no such thing as a unique shape,” says Classoux, of the University of Rennes in France. “There [are] Various shapes are possible. ” These forms are known as “metastable states.”
In a series of experiments, the researchers stretched squares of knitted fabric, made using a basic knitting technique known as stockinette knitting, onto a rectangular frame. The force was then released and the length to width ratio of the swatch was measured. The ratio depends on how much the fabric is stretched and in which direction, indicating that the fabric can assume different metastable states.
Computer simulations of simplified fiber loops showed the same effect. And when scientists reduced or removed friction in their simulations, many of the metastable states disappeared. Without friction, the dough will always return to the same shape.
This phenomenon helps explain a process knitters often experience after knitting a garment, known as “blocking,” where the fabric is wetted, shaped, and then spread out to dry. This process locks the fabric into the proper shape and hugs you warmly.
