Knee ligament failure under dynamic loadings
Résumé
A new experimental device was designed to study the failure properties of knee ligaments under dynamic loadings like those undergoing during pedestrian impacts. This device consists of a hydraulic actuator in order to impose various loading conditions on isolated knee ligaments. The originality of this device leads in the ligaments locking system obtained with spherical joint. Each sample is obtained with an isolated bone-ligament-bone complex embedded in resin. The sample can then be tested for various orientations of ligaments during loading. Results were obtained on twenty human ligaments subjected to tensile traction tests in their fibre axes at 2m/s velocity. These results show that knee ligaments failure properties can be classified into two groups corresponding to the cruciate and the lateral ligaments. For each group it was also possible to identify specific damage pattern (with peeling failure and bone avulsion), failure mode (ductile and brittle for lateral and cruciate ligaments), damage localisation and deformation failure for both groups. These results were also used to validate a damage model for soft tissue structures.
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