Structure-function relations in mammalian tendon: the effect of geometrical nonuniformity.

The stress-strain relations of mammalian tendon are analyzed in terms of the structure of its constituents. Two observed experimental features are accounted for by the present model: the effect of the elastic fibers on the stress-strain curve in the primary range and the effect of the geometrical diversity of the structural units of the collagen fibers on the nonlinearity of the stress-strain relations. The effect of the matrix-fiber interaction and the bending rigidity of the fiber are neglected. It is shown that the observed nonlinear characteristics of the stress-strain relations in the tendon can be accurately accounted for by the model. It is further shown that on the basis of this model, considerable insight into the structure and mechanics of the tendon's constituents can be obtained from results of simple stress-strain tests.