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The viscoelastic deformation of tendon

1980; Elsevier BV; Volume: 13; Issue: 6 Linguagem: Inglês

10.1016/0021-9290(80)90345-0

1873-2380

C. J. Hooley, N. G. McCrum, Robert E. Cohen,

Cellular Mechanics and Interactions

The viscoelastic deformation of tendon has been studied in the 'toe' and 'linear' regions of the stress-strain curve. The apparent activation energy, ΔHa, of the viscoelastic deformation process was determined by the temperature change (or T-jump) technique. Experiments were carried out in creep, creep-recovery and stress relaxation for a variety of specimens. A gradual transition was observed from the value of ΔHa = 12 ± 3 kcal/mol in the 'toe' region to ΔHa = 33 ± 3 kcal/mol in the 'linear' region. The observed transition in ΔHa coincided with two other major changes in the tendon behaviour; (i) a transition from the 'toe' to the 'linear' region of the stress-strain curve, and (ii) a change from a concave downward curve to an approximately linear region on an isochronal plot of creep rate against load. A value of ΔHa = 32 kcal/mol was also found for a preloaded tendon in the 'linear' region of the stress-strain curve and for a specimen of collagen tape, which is devoid of all mucopolysaccharides. The measured activation energies indicate that there are different deformation mechanisms occurring in the 'toe' and 'linear' regions of the stress-strain curve of tendon. It is proposed that the viscoelastic mechanism of tendon deformation is one of shear of the mucopolysaccharide gel between the collagen ribbons in the 'toe' region followed by fibrillar extension in the 'linear' region.