Lisa Zyga, Phys.org:
Cotton thread is made of many tiny fibers, each just 2-3 cm long, yet when spun together the fibers are capable of transmitting tension over indefinitely long distances. From a physics perspective, how threads and yarns transmit tension—making them strong enough to keep clothes from falling apart—is a long-standing puzzle that is not completely understood.
In a new paper published in Physical Review Letters entitled “Why Clothes Don’t Fall Apart: Tension Transmission in Staple Yarns,” physicists Patrick Warren at Unilever R&D Port Sunlight, Robin Ball at the University of Warwick, and Ray Goldstein at the University of Cambridge have investigated yarn tension in the framework of statistical physics. Using techniques from linear programming, they show that the collective friction among fibers creates a locking mechanism, and as long as there is sufficient friction, a random assembly of fibers can in principle transmit an indefinitely large tension.