[The biomechanics of hyaline cartilage under distension stress]

The mechanical properties of costal cartilage specimens from cattle were tested under periodical compressive loads. The specimens were put between the compression plates of an electronic materials testing machine and were exposed to defined deformations and deformation rates. On the basis of these induced periodical deformation-time curves as input functions we obtained force-time curves as output functions.

(1) The cyclic force-time curves generated by deformation-time input functions with constant amplitudes initially showed a general decrease of force peaks until a force-time curve with constant amplitudes gradually arose. (2) If periodically loaded after a constant deformation had taken place the force peaks increased, at first pronouncedly but later diminishing. We named this the 'peak increase phenomenon'. (3) The mechanorheological curves of hyaline cartilage can be explained approximately by the viscoelastic behaviour of microfibrils in a parallel arrangement with the elastoviscous properties of cartilaginous ground substance.