title: The non-linear viscoelastic behaviour of human hair at moderate extensions.
abstract: We report the results of experiments carried out on the stress relaxation of slightly stretched human hair. The results show that human hair is viscoelastic, and that when quickly extended to a moderate degree (0.5-6.5%) and held, the force generated will fall to half its original value in about 15 h. However, the relaxation process is also dependent on extension, so that iso-chronous (constant time) data is non-Hookean. We show that the iso-chronous stress/strain behaviour departs from linearity at about 1% extension and the modulus progressively decreases thereafter according to a power-law relationship with strain.
authors.affiliation: Unilever Research, Port Sunlight, Wirral CH63 3JW, U.K.
authors.forename: H A
authors.initials: HA
authors.lastname: Barnes
authors.forename: G P
authors.initials: GP
authors.lastname: Roberts