PURE MOMENT TESTING FOR SPINAL BIOMECHANICS APPLICATIONS: FIXED VERSUS 3D FLOATING RING CABLE-DRIVEN TEST DESIGNS

摘要

Results show the potential of the fixed ring cable-driven system to deviate from a pure moment loading state. Differences between applied and intended moments were consistently higher for the fixed versus 3D floating ring set-up with the greatest differences in flexion-extension and lateral bending. The fixed ring design also induced non-trivial shear forces. For the 3D floating ring set-up, applied moments remained fairly consistent with intended moments despite varying specimen rigidity and length. Its main advantage is its ability to allow additional directions of unconstrained motion with the linear sliders and vertical bearings on the loading ring.