STRESS-STRAIN RELATION FOR SKIN

A simple model of the collagen fiber network in the dermis is used to calculate the strain level at which the stiffness of skin abruptly increases. The calculated critical strain level (57%) agrees roughly with experimental values. It is suggested that entry into the high-modulus region of the stress-strain curve of skin is simply a geometric effect, corresponding to thorough alignment, along the stress direction, of the fibers in the collagen network. The model finds use in systematizing data on the effect of age on the long-range extensibility of skin and on the morphological basis of skin extensibility along and across Langer's lines. © 1979.